CVE-2026-59822: litellm litellm

CVSS 8.8 (high) · listed as exploited by CISA since 2026-09-02 · published 2026-07-08

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.84.0, LiteLLM's MCP Streamable HTTP endpoint allowed an unauthenticated attacker to use a fabricated Authorization header to trigger an OAuth2 passthrough fallback path that replaced failed LiteLLM key validation with an empty UserAPIKeyAuth() object, allowing requests to reach MCP tooling without a valid LiteLLM key. This issue is fixed in version 1.84.0.

Affected products (NVD): litellm litellm

Fixed in (NVD): 1.84.0

Weakness: CWE-287, CWE-306

Source: NVD CVE-2026-59822

References

• https://github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c
• https://github.com/BerriAI/litellm/pull/26463
• https://github.com/BerriAI/litellm/releases/tag/v1.84.0
• https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-59822
• https://www.wiz.io/blog/ai-infrastructure-honeypot

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