GHSA-3x77-wg38-92r3: mcp-shell has a Secure Mode Allowlist Bypass via Default `/bin/bash` Executable

Summary

mcp-shell's default Docker configuration (security.yaml) includes /bin/bash in allowed_executables, and the command validator in security.go checks only the first token, so it does not block shell flags such as -c. Any MCP tool caller can send command=/bin/bash -c <arbitrary-command> to shell_exec, with no authentication or configuration changes needed, and run binaries outside the allowlist as mcpuser inside the container.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

Topics

• Model Context Protocol

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