https://cve.radiocsirt.org/rss/recent/all/10 Most recent entries from all 2026-10-25T01:51:47.346671+00:00 Vulnerability-Lookup csirt@opendfir.org python-feedgen Contains only the most 10 recent entries. https://cve.radiocsirt.org/vuln/cve-2021-41194 CVE-2021-41194 — Improper Access Control in jupyterhub-firstuseauthenticator 2026-10-25T01:51:47.467902+00:00

Affected: jupyterhub firstuseauthenticator

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.

 https://cve.radiocsirt.org/vuln/ghsa-5xvc-vgmp-jgc3 GHSA-5xvc-vgmp-jgc3 — Improper Access Control in jupyterhub-firstuseauthenticator 2026-10-25T01:51:47.468011+00:00

Affected: PyPI: jupyterhub-firstuseauthenticator

### Impact

When JupyterHub is used with FirstUseAuthenticator, the vulnerability allows unauthorized access to any user's account if `create_users=True` and the username is known or guessed.

### Patches

Upgrade to jupyterhub-firstuseauthenticator to 1.0, or apply patch https://github.com/jupyterhub/firstuseauthenticator/pull/38.patch

### Workarounds

If you cannot upgrade, there is no complete workaround, but it can be mitigated.

If you cannot upgrade yet, you 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. If any users have never logged in with their normalized username (i.e. lowercase), they will still be vulnerable until you can patch or upgrade.