---
id: CVE-2026-12773
aliases:
  - GHSA-4jcj-7x88-m979
title: 'LiteLLM: MCP Proxy Has Improper Authentication'
summary: 'LiteLLM: MCP Proxy Has Improper Authentication'
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
vendor: litellm
product: litellm
ecosystem: pip
affected:
  - litellm < 1.84.0
patched:
  - litellm 1.84.0
published: '2026-06-21'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T22:45:04.152231756Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-4jcj-7x88-m979'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-12773'
  - url: >-
      https://github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-12773'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2491112'
  - url: 'https://gist.github.com/YLChen-007/3cfaad10a69d7a15e4d4d458cb53309e'
  - url: 'https://github.com/BerriAI/litellm'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12773.json
  - url: 'https://vuldb.com/cve/CVE-2026-12773'
  - url: 'https://vuldb.com/submit/811282'
  - url: 'https://vuldb.com/vuln/372515'
  - url: 'https://vuldb.com/vuln/372515/cti'
  - url: 'https://github.com/advisories/GHSA-4jcj-7x88-m979'
tags:
  - osv
  - pip
  - ghsa
epss: 0.01017
epssPercentile: 0.61747
cwe:
  - CWE-287
  - CWE-303
ingestedAt: '2026-09-10T23:08:11.245Z'
---

## Overview

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.

## Affected packages

- `litellm < 1.84.0`

## Remediation

Upgrade to a patched release:

- `litellm 1.84.0`