CVE-2026-42271

LiteLLM: Authenticated command execution via MCP stdio test endpoints

HIGH

8.8

CVSS Score

Published: May 8, 2026 at 03:35 AM UTC

Updated: October 26, 2026 at 08:10 PM UTC

3 products affected across 3 vendorsOpenShift AILiteLLMLiteLLM

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Severity

HIGH8.8

Exploitation

CISA KEV

Exploit prediction

EPSS 91%

SSVC

Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score91.4%

EPSS (Exploit Prediction Scoring System) estimates a 91.4% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

BerriAI LiteLLM contains a command injection vulnerability that could allow any authenticated user, including holders of low-privilege internal-user keys, to run arbitrary commands on the host.

Required Action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Ransomware Use

Unknown

Added to KEV

Jun 8, 2026

Remediation Due

Jun 22, 2026

129 days overdue

Notes

This vulnerability affects a common open-source component, third-party library, or a protocol used by different products. Please check with specific vendors for information on patching status. For more information, please see: https://github.com/BerriAI/litellm/security/advisories/GHSA-v4p8-mg3p-g94g

https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stable

https://nvd.nist.gov/vuln/detail/CVE-2026-42271

Description

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.74.2 to before version 1.83.7, two endpoints used to preview an MCP server before saving it — POST /mcp-rest/test/connection and POST /mcp-rest/test/tools/list — accepted a full server configuration in the request body, including the command, args, and env fields used by the stdio transport. When called with a stdio configuration, the endpoints attempted to connect, which spawned the supplied command as a subprocess on the proxy host with the privileges of the proxy process. The endpoints were gated only by a valid proxy API key, with no role check. Any authenticated user — including holders of low-privilege internal-user keys — could therefore run arbitrary commands on the host. This issue has been patched in version 1.83.7.