CVE-2026-12773 MEDIUM

CVE-2026-12773: BerriAI litellm MCP Proxy user_api_key_auth_mcp.py UserAPIKeyAuth improper authentication

Vendor Berriai
Product litellm
Weakness CWE-287 · Improper authentication
Published June 21, 2026
Last update June 30, 2026

CVSS base score

6.9/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

June 21, 2026 CVE published
June 30, 2026 Record updated