Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-59822

CVE-2026-59822HIGH

BerriAI litellm — LiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   N   N   N   H   L   N    8.8   .0084   56.3   YES

AFFECTED
  Product  Versions    Fixed
  litellm  < 1.84.0 –  —

TIMELINE
  Jul 7   Reserved by GitHub_M
  Jul 8   Published (CNA: GitHub_M)
  Sep 2   ADDED TO KEV — CVE-2026-59822 (BerriAI litellm). Remediation due September 16, 2026.
  Sep 17  DUE DATE PASSED — CVE-2026-59822 (BerriAI litellm). CISA remediation deadline was September 16, 2026; still in catalog.

CWE-287, CWE-306 · CNA: GitHub_M · CVSS v4.0 · 6 references · NVD status: Analyzed · KEV due September 16, 2026

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.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
July 7, 2026	Reserved	Reserved by GitHub_M
July 8, 2026	Published	Published (CNA: GitHub_M)
September 2, 2026	KEV ADDED	ADDED TO KEV — CVE-2026-59822 (BerriAI litellm). Remediation due September 16, 2026.
September 17, 2026	DUE DATE PASSED	DUE DATE PASSED — CVE-2026-59822 (BerriAI litellm). CISA remediation deadline was September 16, 2026; still in catalog.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
BerriAI	litellm	—	< 1.84.0	—

Weaknesses

CWE-287 · CWE-306

References (6)

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]

Authoritative record: CVE-2026-59822 at cve.org

Vendors: berriai

Weaknesses: CWE-287 · CWE-306

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-59822 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.