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CISA Known Exploited Vulnerability

This CVE is actively exploited in the wild. CISA mandates federal agencies to patch immediately.

CVE

CVE-2026-39987

9.3

CVSScritical

Exploitable remotely over the internet · no authentication required.

Description

marimo is a reactive Python notebook. Prior to 0.23.0, Marimo 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. This vulnerability is fixed in 0.23.0.