CVE-2021-41194

Advisory

FirstUseAuthenticator is a JupyterHub authenticator that helps new users set their password on their first login to JupyterHub. When JupyterHub is used with FirstUseAuthenticator, a vulnerability in versions prior to 1.0.0 allows unauthorized access to any user's account if `create_users=True` and the username is known or guessed. One may upgrade to version 1.0.0 or apply a patch manually to mitigate the vulnerability. For those who cannot upgrade, there is no complete workaround, but a partial mitigation exists. One can disable user creation with `c.FirstUseAuthenticator.create_users = False`, which will only allow login with fully normalized usernames for already existing users prior to jupyterhub-firstuserauthenticator 1.0.0. If any users have never logged in with their normalized username (i.e. lowercase), they will still be vulnerable until a patch or upgrade occurs.

Affected package

Affected versions

Fixed versions

Vulnerability changelog

This vulnerability has no description

Resources

• https://nvd.nist.gov/vuln/detail/CVE-2021-41194
• https://github.com/advisories/GHSA-5xvc-vgmp-jgc3
• https://github.com/jupyterhub/firstuseauthenticator/pull/38.patch
• https://github.com/jupyterhub/firstuseauthenticator/security/advisories/GHSA-5xvc-vgmp-jgc3
• https://github.com/jupyterhub/firstuseauthenticator/pull/38
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41194