CVE-2026-39987
Marimo Remote Code Execution Vulnerability
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Marimo, fix it now.
CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
US federal civilian agencies must remediate by May 7, 2026.
Patch status
Official fix available since
Apply the vendor's update to every affected system. Check the fixed-in versions below where known.
Basis: NVD patch reference
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.
Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.
Affected products
| Product | Vendor | Source |
|---|---|---|
| Marimo | Marimo | KEV |
Sources: KEV = CISA Known Exploited Vulnerabilities catalog. Version details have not been published yet.
Intelligence timeline
Developments from the last 30 days, newest first.
No developments recorded for CVE-2026-39987 in the last 30 days.
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Coverage
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