high

Broad host folder or Docker socket mounted into an MCP container

The container mounts /, a home folder or /var/run/docker.sock.

Why it matters

Mounting the Docker socket gives the server control of every container on the host, which is effectively root. Mounting a home folder exposes SSH keys and browser profiles.

How to fix it

Mount only the folder the server works on, read-only where possible (:ro).

Before

{
  "mcpServers": {
    "files": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-v",
        "/var/run/docker.sock:/var/run/docker.sock",
        "acme/mcp-files:2.0.1"
      ]
    }
  }
}

After

{
  "mcpServers": {
    "files": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-v",
        "/home/alex/projects/site:/work:ro",
        "acme/mcp-files:2.0.1"
      ]
    }
  }
}

Illustrative configs. The checker flags the “before” version with this finding and not the “after” version.

Check your own config