CVE-2021-41194

Description

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.

How to fix CVE-2021-41194

To remediate CVE-2021-41194, upgrade the affected package to a fixed version below.

• —upgrade to 1.0.0 or later
• —upgrade to 1.0.0 or later

Is CVE-2021-41194 being exploited?

Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 1.0.0
• from 0, < 1.0.0

CVSS scores

References (9)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-41194
• PATCHgithub.com/jupyterhub/firstuseauthenticator
• WEBgithub.com/jupyterhub/firstuseauthenticator/commit/953418e2450dbc2d854e332350849533b0ebc7ba
• WEBgithub.com/jupyterhub/firstuseauthenticator/pull/38