Improper Authentication in LiteLLM - CVE-2026-35030

 

Improper Authentication in LiteLLM - CVE-2026-35030

Published: April 7, 2026


Vulnerability identifier: #VU125066
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-35030
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to bypass authentication and assume a legitimate user's identity and permissions.

The vulnerability exists due to improper authentication in the OIDC userinfo cache when processing JWT authentication tokens with colliding cache keys. A remote attacker can craft a token whose first 20 characters match a legitimate user's cached token to bypass authentication and assume a legitimate user's identity and permissions.

Only deployments with JWT/OIDC authentication enabled are vulnerable, and the issue depends on a cached legitimate user's token being present.


Affected software

LiteLLM
Python for Scientific Computing

How to mitigate CVE-2026-35030

Install security update from vendor's website.

LiteLLM - update to 1.83.0
Python for Scientific Computing - update to 4.3.2

External References

Related Security Bulletins