Impact

Users of JupyterLab with JupyterHub who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place.

Patches

Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the user environment that needs patching. There are no patches necessary in the Hub environment.

Workarounds

The only workaround is to make sure that only one JupyterLab tab is open when you log out.

References

• GHSA-cw7p-q79f-m2v7
• jupyterhub/jupyterhub@5ac9e7f
• https://nvd.nist.gov/vuln/detail/CVE-2021-41247