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Vulnerability · Published Jun 21, 2026 · Assigned by VulDB

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

High 7.3

In plain English

A high-severity improper authentication in litellm from BerriAI. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 63% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.3High
Exploit odds (30 days)1.0%top 36.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

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 & fixed versions

EcosystemPackageFixed inAdvisory
PyPIlitellm1.84.0GHSA-4jcj-7x88-m979
PyPIlitellm1.84.0PYSEC-2026-4067

Affected products (as reported)

VendorProductVersions
BerriAI litellm 1.59.01.59.11.59.21.59.31.59.41.59.51.59.61.59.7

Weakness: CWE-287, CWE-303 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R

References