Affected versions of Cryptography may allow a remote attacker to decrypt captured messages in TLS servers that use RSA key exchanges, which may lead to exposure of confidential or sensitive data.

Affected versions of the cryptography package are vulnerable to Improper Input Validation due to missing prime-order subgroup validation for SECT elliptic-curve points. The public_key_from_numbers, EllipticCurvePublicNumbers.public_key(), load_der_public_key(), and load_pem_public_key() entry points accept attacker-supplied public keys without verifying that the provided point lies in the expected prime-order subgroup, enabling small-subgroup points to pass as valid.

Cryptography 41.0.4 updates Windows, macOS, and Linux wheels to be compiled with OpenSSL 3.1.3, that includes a security fix.
https://github.com/pyca/cryptography/commit/fc11bce6930e591ce26a2317b31b9ce2b3e25512

Cryptography 39.0.1 includes a fix for CVE-2022-3996, a DoS vulnerability affecting openssl.
https://github.com/pyca/cryptography/issues/7940

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

Cryptography version 42.0.5 introduces a limit on the number of name constraint checks during X.509 path validation to prevent denial of service attacks.
https://github.com/pyca/cryptography/commit/4be53bf20cc90cbac01f5f94c5d1aecc5289ba1f

Cryptography 3.3 no longer allows loading of finite field Diffie-Hellman parameters of less than 512 bits in length. This change is to conform with an upcoming OpenSSL release that no longer supports smaller sizes. These keys were already wildly insecure and should not have been used in any application outside of testing.
https://github.com/pyca/cryptography/pull/5592

Cryptography 41.0.5 updates Windows, macOS, and Linux wheels to be compiled with OpenSSL 3.1.4, that includes a security fix.

Cryptography 41.0.0 updates its dependency 'OpenSSL' to v3.1.1 to include a security fix.
https://github.com/pyca/cryptography/commit/8708245ccdeaff21d65eea68a4f8d2a7c5949a22

The `cryptography` library has updated its BoringSSL and OpenSSL dependencies in CI due to a security concern. Specifically, the issue involves the functions `EVP_PKEY_param_check()` and `EVP_PKEY_public_check()`, which are used to check DSA public keys or parameters. These functions can experience significant delays when processing excessively long DSA keys or parameters, potentially leading to a Denial of Service (DoS) if the input is from an untrusted source. The vulnerability arises because the key and parameter check functions do not limit the modulus size during checks, despite OpenSSL not allowing public keys with a modulus over 10,000 bits for signature verification. This issue affects applications that directly call these functions and the OpenSSL `pkey` and `pkeyparam` command-line applications with the `-check` option. The OpenSSL SSL/TLS implementation is not impacted, but the OpenSSL 3.0 and 3.1 FIPS providers are affected by this vulnerability.

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

Cryptography starting from version 42.0.0 updates its CI configurations to use newer versions of BoringSSL or OpenSSL as a countermeasure to CVE-2023-5678. This vulnerability, affecting the package, could cause Denial of Service through specific DH key generation and verification functions when given overly long parameters.

Cryptography 41.0.3  updates its bundled OpenSSL version to include a fix for CVE-2023-2975: AES-SIV implementation ignores empty associated data entries.
https://github.com/pyca/cryptography/commit/bfa4d95f0f356f2d535efd5c775e0fb3efe90ef2
https://www.openssl.org/news/secadv/20230714.txt

The cryptography library has updated its OpenSSL dependency in CI due to security concerns. This vulnerability arises when processing maliciously formatted PKCS12 files, which can cause OpenSSL to crash, leading to a potential Denial of Service (DoS) attack. PKCS12 files, often containing certificates and keys, may come from untrusted sources. The PKCS12 specification allows certain fields to be NULL, but OpenSSL does not correctly handle these cases, resulting in a NULL pointer dereference and subsequent crash. Applications using OpenSSL APIs, such as PKCS12_parse(), PKCS12_unpack_p7data(), PKCS12_unpack_p7encdata(), PKCS12_unpack_authsafes(), and PKCS12_newpass(), are vulnerable if they process PKCS12 files from untrusted sources. Although a similar issue in SMIME_write_PKCS7() was fixed, it is not considered significant for security as it pertains to data writing. This issue does not affect the FIPS modules in versions 3.2, 3.1, and 3.0.

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

Cryptography 41.0.3 updates its bundled OpenSSL version to include a fix for a Denial of Service vulnerability.
https://github.com/pyca/cryptography/commit/bfa4d95f0f356f2d535efd5c775e0fb3efe90ef2
https://www.openssl.org/news/secadv/20230719.txt

Cryptography 3.3.2 includes a fix for CVE-2020-36242: certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow, as demonstrated by the Fernet class.

Cryptography 3.2 and prior are vulnerable to Bleichenbacher timing attacks in the RSA decryption API, via timed processing of valid PKCS#1 v1.5 ciphertext.

A flaw was found in python-cryptography versions between >=1.9.0 and <2.3. The finalize_with_tag API did not enforce a minimum tag length. If a user did not validate the input length prior to passing it to finalize_with_tag an attacker could craft an invalid payload with a shortened tag (e.g. 1 byte) such that they would have a 1 in 256 chance of passing the MAC check. GCM tag forgeries can cause key leakage. See: CVE-2018-10903.

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

The cryptography package before 41.0.2 for Python mishandles SSH certificates that have critical options.

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

Cryptography 41.0.3 updates its bundled OpenSSL version to include a fix for a Denial of Service vulnerability.
https://github.com/pyca/cryptography/commit/b22271cf3c3dd8dc8978f8f4b00b5c7060b6538d
https://www.openssl.org/news/secadv/20230731.txt

Cryptography 39.0.1 updates its dependency 'OpenSSL' to v3.0.8 to include security fixes.
https://github.com/pyca/cryptography/issues/8229

Cryptography 39.0.1 includes a fix for CVE-2023-23931: In affected versions 'Cipher.update_into' would accept Python objects which implement the buffer protocol, but provide only immutable buffers. This would allow immutable objects (such as 'bytes') to be mutated, thus violating fundamental rules of Python and resulting in corrupted output. This issue has been present since 'update_into' was originally introduced in cryptography 1.8.