CVE-2026-12773

Name: CVE-2026-12773
Creator: NVD / NIST
Published: 2026-06-21T04:16:28.23+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.60%

Last modified Jun 24, 2026

CVE-2026-12773 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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. EPSS estimates a 0.60% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

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

CVSS 4.0

5.5/10

CVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.60%

44.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
Litellm	Litellm	< 1.59.9

References

https://gist.github.com/YLChen-007/3cfaad10a69d7a15e4d4d458cb53309eExploit, Third Party Advisory
https://vuldb.com/cve/CVE-2026-12773Third Party Advisory, VDB Entry
https://vuldb.com/submit/811282Third Party Advisory, Exploit, VDB Entry
https://vuldb.com/vuln/372515Third Party Advisory, VDB Entry
https://vuldb.com/vuln/372515/ctiPermissions Required, VDB Entry
https://vuldb.com/submit/811282Third Party Advisory, Exploit, VDB Entry

Timeline

Published: Jun 21, 2026
Last Modified: Jun 24, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-12773?

How severe is CVE-2026-12773?

CVE-2026-12773 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.60% probability of exploitation in the next 30 days.

How do I fix CVE-2026-12773?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-12773?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST