This vulnerability is being actively exploited in the wild, according to the CISA Known Exploited Vulnerabilities catalog. CISA added it on September 2, 2026.

HighVulnerabilityLLM-specific

CVE-2026-59822: LiteLLM authentication bypass through MCP Streamable HTTP endpoint

Source: NVD(opens in a new tab)
Identifier: CVE-2026-59822
Published: July 8, 2026
Record updated: October 10, 2026

View JSON

Affected: litellm < 1.84.0
Fixed in: 1.84.0
Known exploitation: Listed in the CISA Known Exploited Vulnerabilities catalog since September 2, 2026.
EPSS: 0.8%

Summary

CVE-2026-59822 affects LiteLLM versions prior to 1.84.0. An unauthenticated attacker could send a fabricated Authorization header to the MCP Streamable HTTP endpoint, triggering an OAuth2 passthrough fallback that replaces failed key validation with an empty UserAPIKeyAuth() object. This lets requests reach MCP tooling without a valid LiteLLM key. The GitHub-assigned CVSS 4.0 base score is 8.8 (HIGH), and CWE-287 and CWE-306 are listed.

Mitigation

Fixed in 1.84.0.

Details

Scores and exploitation

Patch available: Yes
EPSS: 0.8%Estimated probability that this CVE is exploited in the next 30 days, from the FIRST Exploit Prediction Scoring System. Read on October 13, 2026.
Known exploitation: Listed in CISA KEV, exploited in the wild
Disclosure date: July 8, 2026

Weaknesses and techniques

Weakness (CWE): CWE-287
CWE-306
Attack pattern (CAPEC): CAPEC-114
CAPEC-115

Affected

Packages: litellm@< 1.84.0 (fixed: 1.84.0)
Vendors: LangChain

Classification

Attack type: Other
Attack sophistication: Trivial
AI component targeted: API
Impact: Confidentiality,
Integrity
Labels: security

How this record was produced

Summaries, mitigations and labels on this page are generated automatically from the source. The linked source is authoritative. The source gives this advisory a description and no title, so the title above is a headline generated from the source text.

Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-59822

First tracked: July 8, 2026 at 08:07 PM ET, from NVD/CVE Database

Classifier: claude-haiku-5-5, prompt v4

Classifier confidence: 93% (self-assessed)

Affected packages in the Exposure Registry

Matched by package name and ecosystem. Each entry shows whether the package delegates to a language model and how many tracked packages depend on it.

litellmPyPILLM dependency since 2023-07-27 · 54 tracked dependents

Coverage

News, research and other items that mention CVE-2026-59822.

Top MCP security resources — October 2026Adversa AI Blog · 2026-10-08
Off Guard: Breaking LiteLLM from authentication bypass to cloud compromiseWiz Research Blog · 2026-09-09

Topics

Model Context Protocol

Summary

Mitigation

Affected packages in the Exposure Registry

Coverage

Topics

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