CVE-2026-39987
Marimo Remote Code Execution Vulnerability
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.
CRITICAL · CVSS 9.8
⚠ CISA KEV
EPSS 0.79886
Act now
- Listed on CISA KEV (known exploited in the wild)
- SSVC exploitation status: active
- EPSS ≥ 0.50 - high probability of exploitation in the next 30 days
- EPSS percentile: top 1% of all CVEs by exploitation likelihood
- Public exploit or PoC is available
- SSVC automatable: yes - attacks can be scripted at scale
- CVSS base score ≥ 7.0
Sigma rules0
YARA rules0