BerriAI litellm <=1.59.8 MCP Proxy auth flaw (UserAPIKeyAuth)
CVE-2026-12773 Published on June 21, 2026

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/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.

NVD

Vulnerability Analysis

CVE-2026-12773 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. An automatable proof of concept (POC) exploit exists. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
LOW
Integrity Impact:
LOW
Availability Impact:
LOW

Timeline

Advisory disclosed

VulDB entry created

VulDB entry last update

Weakness Types

What is an authentification Vulnerability?

When an actor claims to have a given identity, the software does not prove or insufficiently proves that the claim is correct.

CVE-2026-12773 has been classified to as an authentification vulnerability or weakness.

Incorrect Implementation of Authentication Algorithm

The requirements for the software dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect. This incorrect implementation may allow authentication to be bypassed.


Products Associated with CVE-2026-12773

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-12773 are published in these products:

Litellm
 
Red Hat Exploit Intelligence
 
Red Hat Ansible Automation Platform
 
Red Hat Openshift Ai
 

Affected Versions

BerriAI litellm: Red Hat Exploit Intelligence: Red Hat Ansible Automation Platform 2: Red Hat Ansible Automation Platform 2: Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI): Red Hat OpenShift AI (RHOAI):