GHSA-5xvc-vgmp-jgc3

Improper Access Control in jupyterhub-firstuseauthenticator

Source: GitHub Advisory Database (reviewed) Critical CVE-2021-41194

Packages

Ecosystem	Package	Affected	Fixed in
PyPI	jupyterhub-firstuseauthenticator	< 1.0.0	1.0.0

Details

As written in the advisory (Markdown source, shown as plain text).

### 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.

References

External links from the advisory. They lead to third-party sites.