Auth bypass in Berriai Litellm
CVE-2026-12773
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.010 (61.9th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 61.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000
Affected products
- Berriai Litellm — versions 1.59.0, 1.59.1, 1.59.2
- Litellm
Weakness classification (CWE)
References
- vuldb.com/vuln/372515 (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
- vuldb.com/vuln/372515/cti (signature, Permissions Required, permissions-required, VDB Entry)
- vuldb.com/cve/CVE-2026-12773 (VDB Entry, Third Party Advisory, third-party-advisory)
- vuldb.com/submit/811282 (Exploit, VDB Entry, Third Party Advisory, third-party-advisory)
- gist.github.com/YLChen-007/3cfaad10a69d7a15e4d4d458cb53309e (Exploit, Third Party Advisory, exploit)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-12773?
- CVE-2026-12773 is a high-severity vulnerability in Berriai Litellm, classified under Improper Authentication. CVSS score: 7.3/10. Published 2026-06-21.
- How severe is CVE-2026-12773?
- High severity. CVSS v3 base score is 7.3 out of 10.