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GHSA-jjhc-v7c2-5hh6

LiteLLM: Authentication bypass via OIDC userinfo cache key collision

Source: GitHub Advisory Database (reviewed) Critical CVE-2026-35030

Packages

EcosystemPackageAffectedFixed in
PyPI litellm < 1.83.0 1.83.0

Details

As written in the advisory (Markdown source, shown as plain text).

### 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.

References

External links from the advisory. They lead to third-party sites.