Description

CERT Polska has received a report about vulnerability in Code Runner MCP Server software and participated in coordination of its disclosure.

The vulnerability CVE-2026-5029: A remote code execution vulnerability exists in Code Runner MCP Server when run with the --transport http option, which exposes the /mcp JSON-RPC endpoint without authentication on port 3088. An unauthenticated remote attacker can invoke the run-code MCP tool to supply arbitrary source code and execute it via child_process.exec() using the specified language interpreter. This allows execution of arbitrary code with the privileges of the user running the server.

This vulnerability has not been fixed and might affect the project in all versions.

Credits

We thank Eryk Winiarz for the responsible vulnerability report.