CVE-2026-59822

HIGH

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.

CVSS v3.1 Score

8.2
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Published: 7/8/2026Modified: 10/25/2026

Related Intelligence (2)

HIGHVulnerability

CISA KEV: BerriAI LiteLLM — BerriAI LiteLLM Improper Authentication Vulnerability

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.

CVE-2026-59822BerriAI LiteLLM
CISA KEV
HIGHVulnerability

NVD HIGH: CVE-2026-59822 — LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) fo...

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 va

CVE-2026-59822
NIST NVD

References (6)

https://github.com/BerriAI/litellm/commit/73869f0faf7d11ee21adcb5f91b8c33a340b6c2cPatchhttps://github.com/BerriAI/litellm/pull/26463Issue TrackingPatchhttps://github.com/BerriAI/litellm/releases/tag/v1.84.0ProductRelease Noteshttps://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95qMitigationPatchhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-59822US Government Resourcehttps://www.wiz.io/blog/ai-infrastructure-honeypotThird Party Advisory