Insufficient Session Expiration in jupyterhub - CVE-2021-41247
Published: November 4, 2021 / Updated: April 28, 2026
Vulnerability identifier: #VU128393
CSH Severity: Low
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-41247
CWE-ID: CWE-613
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
jupyterhub
jupyterhub
Software vendor:
jupyterhub
jupyterhub
Description
The vulnerability allows a remote user to regain access to the single-user server after logout.
The vulnerability exists due to insufficient session expiration in the JupyterHub single-user server session handling when logging out with another active JupyterLab session open in the same browser session. A remote user can keep multiple JupyterLab tabs open and log out in one tab to regain access to the single-user server after logout.
The issue affects fresh credentials for the single-user server only, not the Hub.
Remediation
Install security update from vendor's website.