GHSA-2679-6mx9-h9xc

Описание

Summary

Marimo (19.6k stars) has a Pre-Auth RCE vulnerability. The terminal WebSocket endpoint /terminal/ws lacks authentication validation, allowing an unauthenticated attacker to obtain a full PTY shell and execute arbitrary system commands.

Unlike other WebSocket endpoints (e.g., /ws) that correctly call validate_auth() for authentication, the /terminal/ws endpoint only checks the running mode and platform support before accepting connections, completely skipping authentication verification.

Affected Versions

Marimo <= 0.20.4

Vulnerability Details

Root Cause: Terminal WebSocket Missing Authentication

marimo/_server/api/endpoints/terminal.py lines 340-356:

Compare with the correctly implemented /ws endpoint (ws_endpoint.py lines 67-82):

Authentication Middleware Limitation

Marimo uses Starlette's AuthenticationMiddleware, which marks failed auth connections as UnauthenticatedUser but does NOT actively reject WebSocket connections. Actual auth enforcement relies on endpoint-level @requires() decorators or validate_auth() calls.

The /terminal/ws endpoint has neither a @requires("edit") decorator nor a validate_auth() call, so unauthenticated WebSocket connections are accepted even when the auth middleware is active.

Attack Chain

1. WebSocket connect to ws://TARGET:2718/terminal/ws (no auth needed)
2. websocket.accept() accepts the connection directly
3. pty.fork() creates a PTY child process
4. Full interactive shell with arbitrary command execution
5. Commands run as root in default Docker deployments

A single WebSocket connection yields a complete interactive shell.

Proof of Concept

Reproduction Environment

Reproduction Result

With auth enabled (server generates random access_token), the exploit bypasses authentication entirely:

Suggested Remediation

1. Add authentication validation to /terminal/ws endpoint, consistent with /ws using WebSocketConnectionValidator.validate_auth()
2. Apply unified authentication decorators or middleware interception to all WebSocket endpoints
3. Terminal functionality should only be available when explicitly enabled, not on by default

Impact

An unauthenticated attacker can obtain a full interactive root shell on the server via a single WebSocket connection. No user interaction or authentication token is required, even when authentication is enabled on the marimo instance.