Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.

Affected versions of Idna are vulnerable to Denial Of Service via the idna.encode(), where a specially crafted argument could lead to significant resource consumption. In version 3.7, this function has been updated to reject such inputs efficiently, minimizing resource use. A practical workaround involves enforcing a maximum domain name length of 253 characters before encoding, as the vulnerability is triggered by unusually large inputs that normal operations wouldn't encounter.

Affected versions of the idna package are vulnerable to Denial of Service due to an incomplete fix for CVE-2024-3651 that still allows specially crafted inputs to consume significant resources during encoding. The idna.encode() function invokes the valid_contexto validator on every label before applying length-based rejection, so payloads such as long repetitions of the Arabic-Indic digit U+0660 or sequences of the Katakana middle dot U+30FB followed by a CJK character cause valid_contexto to perform extensive context-rule processing across each character. A remote attacker who can supply domain-name input to an application that calls idna.encode() without first enforcing the 253-character DNS length limit can submit arbitrarily large strings that drive the validator to exhaust CPU time, resulting in Denial of Service through resource consumption.

Urllib3's ProxyManager ensures that the Proxy-Authorization header is correctly directed only to configured proxies. However, when HTTP requests bypass urllib3's proxy support, there's a risk of inadvertently setting the Proxy-Authorization header, which remains ineffective without a forwarding or tunneling proxy. Urllib3 does not recognize this header as carrying authentication data, failing to remove it during cross-origin redirects. While this scenario is uncommon and poses low risk to most users, urllib3 now proactively removes the Proxy-Authorization header during cross-origin redirects as a precautionary measure. Users are advised to utilize urllib3's proxy support or disable automatic redirects to handle the Proxy-Authorization header securely. Despite these precautions, urllib3 defaults to stripping the header to safeguard users who may inadvertently misconfigure requests.

Affected versions of the urllib3 package are vulnerable to Information Disclosure due to improper handling of sensitive headers during cross-origin redirects in the low-level proxy API. When following cross-origin redirects via ProxyManager.connection_from_url().urlopen() with assert_same_host=False, sensitive headers including Authorization, Cookie, and Proxy-Authorization are not stripped, unlike the high-level API, which removes them via Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT. An attacker controlling a redirect target can capture these sensitive headers from requests that follow cross-origin redirects through the low-level proxy API path.

Urllib3 1.25.9 includes a fix for CVE-2020-26137: Urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
https://github.com/python/cpython/issues/83784
https://github.com/urllib3/urllib3/pull/1800

urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects. By default, requests and botocore users are not affected. An application attempting to mitigate SSRF or open redirect vulnerabilities by disabling redirects at the PoolManager level will remain vulnerable. This issue has been patched in version 2.5.0.

Affected versions of urllib3 are vulnerable to an HTTP redirect handling vulnerability that fails to remove the HTTP request body when a POST changes to a GET via 301, 302, or 303 responses. This flaw can expose sensitive request data if the origin service is compromised and redirects to a malicious endpoint, though exploitability is low when no sensitive data is used. The vulnerability affects automatic redirect behavior. It is fixed in versions 1.26.18 and 2.0.7; update or disable redirects using redirects=False.
This vulnerability is specific to Python's urllib3 library.

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2). See: CVE-2020-7212.

Urllib3 1.26.17 and 2.0.5 include a fix for CVE-2023-43804: Urllib3 doesn't treat the 'Cookie' HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a 'Cookie' header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
https://github.com/urllib3/urllib3/security/advisories/GHSA-v845-jxx5-vc9f

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to improper handling of highly compressed HTTP response bodies during streaming decompression. The urllib3.HTTPResponse methods stream(), read(), read1(), read_chunked(), and readinto() may fully decompress a minimal but highly compressed payload based on the Content-Encoding header into an internal buffer instead of limiting the decompressed output to the requested chunk size, causing excessive CPU usage and massive memory allocation on the client side.

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to redirect handling that drains connections by decompressing redirect response bodies without enforcing streaming read limits. The issue occurs when using urllib3’s streaming mode (for example, preload_content=False) while allowing redirects, because urllib3.response.HTTPResponse.drain_conn() would call HTTPResponse.read() in a way that decoded/decompressed the entire redirect response body even before any streaming reads were performed, effectively bypassing decompression-bomb safeguards.

Urllib3 1.26.5 includes a fix for CVE-2021-33503: When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg

Affected versions of the urllib3 package are vulnerable to Denial of Service (DoS) due to allowing an unbounded number of content-encoding decompression steps for HTTP responses. The HTTPResponse content decoding pipeline in urllib3 follows the Content-Encoding header and applies each advertised compression algorithm in sequence without enforcing a maximum chain length or effective output size, so a malicious peer can send a response with a very long encoding chain that triggers excessive CPU use and massive memory allocation during decompression.

Affected versions of Requests, when making requests through a Requests `Session`, if the first request is made with `verify=False` to disable cert verification, all subsequent requests to the same host will continue to ignore cert verification regardless of changes to the value of `verify`. This behavior will continue for the lifecycle of the connection in the connection pool. Requests 2.32.0 fixes the issue, but versions 2.32.0 and 2.32.1 were yanked due to conflicts with CVE-2024-35195 mitigation.

Affected versions of the requests package are vulnerable to Insecure Temporary File reuse due to predictable temporary filename generation in extract_zipped_paths(). The requests.utils.extract_zipped_paths() utility extracts files from zip archives into the system temporary directory using a deterministic path, and if that file already exists, the function reuses it without validating that it is the expected extracted content.

Affected versions of Requests are vulnerable to proxy credential leakage. When redirected to an HTTPS endpoint, the Proxy-Authorization header is forwarded to the destination server due to the use of rebuild_proxies to reattach the header. This may allow a malicious actor to exfiltrate sensitive information.

Requests is an HTTP library. Due to a URL parsing issue, Requests releases prior to 2.32.4 may leak .netrc credentials to third parties for specific maliciously-crafted URLs. Users should upgrade to version 2.32.4 to receive a fix. For older versions of Requests, use of the .netrc file can be disabled with `trust_env=False` on one's Requests Session.

Certifi 2023.07.22 includes a fix for CVE-2023-37920: Certifi prior to version 2023.07.22 recognizes "e-Tugra" root certificates. e-Tugra's root certificates were subject to an investigation prompted by reporting of security issues in their systems. Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store.
https://github.com/certifi/python-certifi/security/advisories/GHSA-xqr8-7jwr-rhp7

Certifi 2022.12.07 includes a fix for CVE-2022-23491: Certifi 2022.12.07 removes root certificates from "TrustCor" from the root store. These are in the process of being removed from Mozilla's trust store. TrustCor's root certificates are being removed pursuant to an investigation prompted by media reporting that TrustCor's ownership also operated a business that produced spyware. Conclusions of Mozilla's investigation can be found in the linked google group discussion.