Improper Validation of Specified Quantity in Input in jupyterhub - #VU162716
Published: November 9, 2026
Vulnerability identifier: #VU162716
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-1284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an authenticated remote attacker to create non-expiring JupyterHub tokens despite a configured maximum token lifetime.
The vulnerability exists due to inconsistent validation of the expires_in field when token_expires_in_max_seconds requires expiration, with zero accepted during validation but treated as no expiration during token creation. An authenticated remote attacker can submit a token creation request with expires_in set to zero to bypass the expiration policy.
Affected software
jupyterhub
Remediation
Install security update from vendor's website.
jupyterhub - addressed in versions 5.5.3, 6.1.0