Vulnerability Intelligence Report
marimo Affected by Pre-Auth Remote Code Execution via Terminal WebSocket Authentication Bypass
CVE-2026-39987
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.
CISA KEV
Nuclei Template
SSVC: Active Exploitation
Automatable
CVSS Base Score
9.3
CRITICAL
EPSS Probability:95.64%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-306 ↗CWE-306: Missing Authentication for Critical Function
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| marimo-team | marimo | < 0.23.0 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
CISA KEV
ACTIVE IN CATALOG
Nuclei Template
SCANNER AVAILABLE
EPSS Score
95.645%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | GitHub, Inc. · Vendor · USA |
| Reserved | 2026-04-08T00:01:47 |
| Published | 2026-04-09T17:16:55 |
| Last Updated | 2026-04-24T03:55:20 |
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