CVE-2026-12773

BerriAI litellm MCP Proxy user_api_key_auth_mcp.py UserAPIKeyAuth improper authentication

At a glance

Severity: MEDIUM 6.9
EPSS: EPSS 1.02 % · percentile 63 (2026-10-27)
State: PUBLISHED
Published: 2026-06-21
Updated: 2026-07-15
Assigner: VulDB
NVD status: Modified

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.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	MEDIUM 6.9	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	VulDB
CVSS 3.1	HIGH 7.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R	VulDB
CVSS 3.0	HIGH 7.3	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R	VulDB
CVSS 2.0	HIGH 7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P/E:POC/RL:ND/RC:UR	VulDB
CVSS 3.1	HIGH 7.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	redhat-SADP
CVSS 4.0	MEDIUM 5.5	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	NVD · cna@vuldb.com (Secondary)
CVSS 3.1	HIGH 7.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	NVD · cna@vuldb.com (Secondary)
CVSS 3.1	CRITICAL 9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	NVD · nvd@nist.gov (Primary)
CVSS 3.1	HIGH 7.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary)
CVSS 2.0	HIGH 7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P	NVD · cna@vuldb.com (Secondary)

Weaknesses (CWE)

Advisories

GHSA-4jcj-7x88-m979 — LiteLLM: MCP Proxy Has Improper Authentication
PYSEC-2026-4067 — LiteLLM: MCP Proxy Has Improper Authentication

European references

ENISA EUVD · EUVD-2026-38139
GCVE · GCVE-0-2026-12773

Affected configurations (NVD CPE)

cpe:2.3:a:litellm:litellm:*:*:*:*:*:*:*:* < 1.59.9

Affected products

Product	Versions
BerriAI · litellm	affected 1.59.0 ; affected 1.59.1 ; affected 1.59.2 ; affected 1.59.3 ; affected 1.59.4 ; affected 1.59.5

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD