BerriAI litellm — Auth Bypass (CVE-2026-12773)
Date: 2026-06
Affected: litellm/litellm
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2026-12773
CWE: CWE-287
CWE-303
CVSS: 7.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)

A weakness has been identified in BerriAI litellm up to 1.59.8. Affected is the function UserAPIKeyAuth of the file litellm/proxy/_experimental/mcp_server/auth/user_api_key_auth_mcp.py of the component MCP Proxy. Executing a manipulation can lead to improper authentication. The attack may be launched remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure.


Mitigations:

Architectural layers (MAESTRO):