CVE-2026-59822: BerriAI LiteLLM Improper Authentication Vulnerability

CISA Known Exploited Vulnerabilities

Name

BerriAI LiteLLM Improper Authentication Vulnerability

Vendor

BerriAI

Product

LiteLLM

Added to the catalog

2026-09-02

Due date for US federal agencies

2026-09-16

Weaknesses

CWE-287, CWE-306

Catalog version

2026.10.30

BerriAI LiteLLM contains an improper authentication vulnerability in the MCP Streamable HTTP endpoint that could allow an unauthenticated attacker to establish an authenticated MCP session using an arbitrary Bearer token.

Required action (CISA)

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.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q
• https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
• https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
• https://nvd.nist.gov/vuln/detail/CVE-2026-59822

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2026-07-08T20:16:57.683

Last modified

2026-10-25T17:10:00.197

Weaknesses

CWE-287, CWE-306

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.

References

• https://github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c (Patch)
• https://github.com/BerriAI/litellm/pull/26463 (Issue Tracking, Patch)
• https://github.com/BerriAI/litellm/releases/tag/v1.84.0 (Product, Release Notes)
• https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q (Mitigation, Patch, Vendor Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-59822 (US Government Resource)
• https://www.wiz.io/blog/ai-infrastructure-honeypot (Third Party Advisory)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:31.494Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-59822

CVE record

Title (CNA)

LiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback

Assigner

GitHub_M

State

PUBLISHED

Published

2026-07-08T19:32:18.611Z

Updated

2026-09-03T03:56:05.174Z

Problem types

CWE-287: Improper Authentication; CWE-306: Missing Authentication for Critical Function

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.

References

• https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q
• https://github.com/BerriAI/litellm/pull/26463
• https://github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2c
• https://github.com/BerriAI/litellm/releases/tag/v1.84.0

Read on 2026-11-03T02:20:44.718Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/59xxx/CVE-2026-59822.json

GitHub Advisory Database

Also known as / affected packages

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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