CVE-2026-59822

Published Jul 8, 2026

Last updated 14 days ago

Exploit known CVSS high 8.8

MCP

Jwt

Container Security

LiteLLM

OpenAI

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-59822 describes an authentication bypass vulnerability found in LiteLLM, an AI Gateway/proxy server, affecting all versions prior to 1.84.0. The flaw exists within LiteLLM's MCP Streamable HTTP endpoint. An unauthenticated attacker can exploit this vulnerability by providing a fabricated Authorization header. This action triggers an OAuth2 passthrough fallback mechanism that replaces a failed LiteLLM key validation with an empty `UserAPIKeyAuth()` object, thereby granting unauthorized access to MCP tooling and its associated services.

Description: LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.84.0, LiteLLM's MCP Streamable HTTP endpoint allowed an unauthenticated attacker to use a fabricated Authorization header to trigger an OAuth2 passthrough fallback path that replaced failed LiteLLM key validation with an empty UserAPIKeyAuth() object, allowing requests to reach MCP tooling without a valid LiteLLM key. This issue is fixed in version 1.84.0.
Source: security-advisories@github.com
NVD status: Analyzed
Products: litellm

Risk scores

CVSS 4.0

Type: Secondary
Base score: 8.8
Impact score: -
Exploitability score: -
Vector string: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/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
Severity: HIGH

CVSS 3.1

Type: Primary
Base score: 8.2
Impact score: 4.2
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Severity: HIGH

Known exploits

Data from CISA

Vulnerability name: BerriAI LiteLLM Improper Authentication Vulnerability
Exploit added on: Sep 2, 2026
Exploit action due: Sep 16, 2026
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Weaknesses

security-advisories@github.com: CWE-287

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:litellm:litellm:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "0432AF82-95FD-4358-9414-7B41889CEFD2",
            "versionEndExcluding": "1.84.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.