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...