CVE-2026-12773
High
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.
SeverityHigh
CVSS7.3
Exploit probability—
ProductLitellm
PublishedJun 21, 2026
First seenJun 21, 2026
Weakness typeCWE-287Improper authentication
How to fix
Update
- litellm litellm1.59.9 or later
- litellm1.84.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| litellm litellm | v < 1.59.9 | 1.59.9 |
| litellmPyPI | v < 1.84.0 | 1.84.0 |
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