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Actively exploitedCVSS 9.8 · CRITICAL

CVE-2026-39987

Marimo contains an pre-authorization remote code execution vulnerability, allowing an unauthenticated attacked to shell access and execute arbitrary system commands.

View on NVD

Severity

Score: 9.8(CRITICAL)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AV: NETWORK
AC: LOW
PR: NONE
UI: NONE
S: UNCHANGED
C: HIGH
I: HIGH
A: HIGH
Weakness (CWE): CWE-306

CISA KEV

Added to KEV: 2026-04-23
Federal patch deadline: 2026-05-07
Known ransomware use: Unknown
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.

EPSS

Probability of exploitation (next 30 days): 0.5998 (60.0%)
Percentile: 98.3%
EPSS: 2026-05-06

Affects

coreweave:marimo

Technical 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.

Published: 4/9/2026, 6:17:02 PM
Last modified: 4/23/2026, 8:15:29 PM

References

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