What is CVE-2026-42271?
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.
CISA Known Exploited Vulnerability
BerriAI LiteLLM Command Injection Vulnerability
Affected product
BerriAI LiteLLM
Remediation Steps
- Apply security patches from BerriAI for LiteLLM
- Review and restrict input validation on LiteLLM command interfaces
- Audit recent LiteLLM command execution logs for exploitation attempts
- Update to the latest stable version of LiteLLM
References
- https://github.com/BerriAI/litellm/security/advisories/GHSA-v4p8-mg3p-g94g
- https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stable
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42271
- https://nvd.nist.gov/vuln/detail/CVE-2026-42271
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Coverage on defend.network
- Vulnerability Priority Report – Week 2 of June 2026 (June 8 – 14)