CVE-2026-59822
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.
Actively exploited
- In the CISA exploited-vulnerabilities catalogue since Sep 2, 2026
- US federal agencies must remediate it by Sep 16, 2026 (BOD 22-01)
- Attacked 1 day before the vulnerability was made public
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.
Source: CISA KEV · Sep 2, 2026 Sep 2, 2026 Aug 27, 2026 Jul 26, 2026 Jul 8, 2026
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:NAffected products
| Vendors | Prodotto | Versioni |
|---|---|---|
| litellm | litellm | < 1.84.0 |
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