CVE•Published 2026-04-09•Modified 2026-04-23•1 article on news•7 live references•NVD data

CVE-2026-39987Coreweave · Marimo

Vulnerability data via NVD (ingested)

CVSS v3.1

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS percentile

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Weaknesses (CWE)

CWE-306Missing Authentication for Critical Function

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.

Timeline

Published 2026-04-09

Modified 2026-04-23

External references

NVD MITRE Exploit-DB GitHub PoC Sploitus trickest/cve VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-39987

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Coreweave Marimo"

All exposed Coreweave Marimo instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Marimo"

HTTP body or banner mentions "Marimo" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-39987