Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Litellm | Litellm | >= 1.74.2, < 1.83.7 |
Related Weaknesses (CWE)
References
- https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stableProductRelease Notes
- https://github.com/BerriAI/litellm/security/advisories/GHSA-v4p8-mg3p-g94gMitigationPatchVendor Advisory
FAQ
What is CVE-2026-42271?
CVE-2026-42271 is a vulnerability with a CVSS score of 8.8 (HIGH). 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 ...
How severe is CVE-2026-42271?
CVE-2026-42271 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-42271?
Check the references section above for vendor advisories and patch information. Affected products include: Litellm Litellm.