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critical·Network Vulnerabilities·Updated Apr 9, 2026

Marimo <= 0.20.4 - Pre-Auth Terminal WebSocket RCE

Est. Time~10 seconds
Scan TypeGroup Scan
Targetsdomain, subdomain, ipv4
CostFree
2.2k
Times Used
continuous scan runs
0
Continuously Checked
assets under CS
0
Vulnerabilities Found
confirmed findings
References
🔴
CISA Known Exploited Vulnerability
This CVE is actively exploited in the wild. CISA mandates federal agencies to patch immediately.
CVECVE-2026-39987
9.3
CVSScritical
Exploitable remotely over the internet · no authentication required.

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.

Attack Vector
Network
Privileges Req.
None
User Interaction
None
Affected
marimoby marimo-team
< 0.23.0
Updated Sep 9, 2026View on NVD →

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