CVE-2026-35030
LiteLLM has an authentication bypass via OIDC userinfo cache key collision
Description
LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.83.0, 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. Fixed in v1.83.0.
CVSS Vector Breakdown
AV:NAttack VectorAC:LAttack ComplexityPR:NPrivileges RequiredUI:NUser InteractionS:UScopeC:HConfidentialityI:HIntegrityA:NAvailabilityWeaknesses
Affected Products
Attack Graph
Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.
Exploitability
MITRE ATT&CK
2 techniquesReferences
Timeline
Unlock Complete Vulnerability Intelligence
Get the full picture for CVE-2026-35030 and every CVE in our database. Create a free account — no credit card required.
Create Free Account