CVEs / CVE-2026-59822
CVE-2026-59822: BerriAI LiteLLM Improper Authentication Vulnerability
- Known exploited in the CISA KEV catalog since 2 Sep 2026
- high 8.2 CVSS 3.1 (NVD)
- EPSS 0.83% chance of exploitation in the next 30 days, higher than 57% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| BerriAI litellm | < 1.84.0 | — |
| Product | Affected | Fixed in |
|---|---|---|
| litellm (PyPI) | before 1.84.0 | 1.84.0 |
Package versions from GHSA-7488-6r32-c95q.
Exploitation
| In CISA KEV since | 2 Sep 2026 |
|---|---|
| Due date for US federal agencies | 16 Sep 2026 |
| Used in ransomware campaigns | Unknown |
| Required action | 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. |
Severity
| CVSS 3.1 | 8.2 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:NScored by NVD |
|---|---|
| Weakness | CWE-287, CWE-306 |
References
- CVE-2026-59822 on NVD
- CVE-2026-59822 in the CISA KEV catalog
- https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- CVE-2026-59822 on OSV
- 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
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.