Bug 2467924 (CVE-2026-42271)

Summary: CVE-2026-42271 litellm: LiteLLM: Authenticated command execution via MCP stdio test endpoints
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: dschmidt, erezende, jkoehler, jlanda, jwong, kshier, lphiri, omaciel, simaishi, smcdonal, stcannon, teagle, ttakamiy, yguenane
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in LiteLLM, a proxy server (AI Gateway) for Large Language Model (LLM) APIs. Two endpoints, used for previewing an MCP server before saving it, accepted a full server configuration including command execution parameters. An authenticated user, even with low-privilege internal-user keys, could exploit this by sending a crafted configuration. This allows for arbitrary command execution on the proxy host with the privileges of the proxy process.
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Description OSIDB Bzimport 2026-05-08 04:02:35 UTC 
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.