CVE-2026-12773: BerriAI litellm MCP Proxy user_api_key_auth_mcp.py UserAPIKeyAuth improper authentication
A weakness has been identified in BerriAI litellm up to 1.59.8. Affected is the function UserAPIKeyAuth of the file litellm/proxy/experimental/mcpserver/auth/userapikeyauthmcp.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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-12773?
The severity of CVE-2026-12773 is rated high with a score of 7.3.
How do I fix CVE-2026-12773?
To fix CVE-2026-12773, update BerriAI litellm to version 1.59.9 or later.
What vulnerability does CVE-2026-12773 represent?
CVE-2026-12773 represents a weakness in the UserAPIKeyAuth function that allows for improper authentication.
Which file is affected by CVE-2026-12773?
CVE-2026-12773 affects the user_api_key_auth_mcp.py file located in litellm/proxy/_experimental/mcp_server/auth.
Who is affected by CVE-2026-12773?
Users of BerriAI litellm versions up to 1.59.8 are affected by CVE-2026-12773.