CVE-2026-35030 LiteLLM has an authentication bypass via OIDC userinfo cache key collision
An attacker can bypass authentication and impersonate users by exploiting OIDC cache key collisions in LiteLLM when JWT authentication is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-35030?
CVE-2026-35030 is a critical authentication bypass vulnerability in BerriAI litellm, published on 6 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-35030?
3 open source packages ship an affected version, including litellm. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
litellm PyPI | All versions | 1.83.0 |
litellm PyPI | All versions | 1.83.0 |
litellm PyPI | All versions | 1.83.0 |
Products include Litellm Litellm.
How do I fix CVE-2026-35030?
Upgrade litellm to 1.83.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-35030 being exploited?
There is no known exploitation of CVE-2026-35030 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in BerriAI litellm
Sources
Also known as CLEANSTART-2026-JK38146, GHSA-jjhc-v7c2-5hh6, MINI-975h-r96j-7xm6, MINI-gc87-9qh7-xh7p, MINI-gv7r-cjh8-p958, MINI-wjjm-x2wv-75pw and 2 more.