PT-2026-53475 · Pypi · Litellm

Published 2026-06-29 · Updated 2026-06-29

OSV

CVSS v4.0

9.4

Critical

Base vector

AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

Impact

When JWT authentication is enabled (enable jwt auth: true), the OIDC userinfo cache uses token[:20] as the cache key. JWT headers produced by the same signing algorithm generate identical first 20 characters.

This configuration option is not enabled by default. Most instances are not affected.

An unauthenticated attacker can craft a token whose first 20 characters match a legitimate user's cached token. On cache hit, the attacker inherits the legitimate user's identity and permissions. This affects deployments with JWT/OIDC authentication enabled.

Patches

Fixed in v1.83.0. The cache key now uses the full hash of the JWT token.

Workarounds

Disable OIDC userinfo caching by setting the cache TTL to 0, or disable JWT authentication entirely.

Fix

Related Identifiers

PYSEC-2026-390

Affected Products

Litellm

References · 6

• https://osv.dev/vulnerability/PYSEC-2026-390 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-35030 · Security Note
• https://github.com/BerriAI/litellm · Note
• https://github.com/BerriAI/litellm/security/advisories/GHSA-jjhc-v7c2-5hh6 · Note
• https://pypi.org/project/litellm · Note
• https://github.com/advisories/GHSA-jjhc-v7c2-5hh6 · Note