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.

CVSS 4.0

5.5CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

CVSS 3.1

9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

1.0% chance of exploitation in the next 30 days; higher than 63% of CVEs (scores of 2026-10-25)

CWEs

CWE-287, CWE-303

Published

2026-06-21

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Affected

• litellm:litellm

Packages (OSV)

References

• https://gist.github.com/YLChen-007/3cfaad10a69d7a15e4d4d458cb53309e
• https://vuldb.com/cve/CVE-2026-12773
• https://vuldb.com/submit/811282
• https://vuldb.com/vuln/372515
• https://vuldb.com/vuln/372515/cti

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