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Findings

CVE-2026-39987

Marimo Remote Code Execution Vulnerability

Published Apr 9, 2026 · updated Jun 17, 2026 · Marimo Marimo

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

Detection, updates, and resolution for this record.

  1. Apr 9, 2026 · Catalog

    Detected

    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 endpo

  2. Apr 23, 2026 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  3. May 7, 2026 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  4. Jun 17, 2026 · Catalog

    Updated

    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 endpo

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.

CISA due date May 7, 2026

Affected

  • cpe coreweave/marimoversion unspecified
  • vendor Marimo Marimoversion unspecified

Sources

  • CISA KEVCVE-2026-39987

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

    cisa.gov
  • CVE.orgCVE-2026-39987

    Official CVE identifier

    cve.org
  • FIRST EPSSCVE-2026-39987

    30-day exploitation probability 37.9%

    first.org
  • Exploit Database52673

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • NIST NVDCVE-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. Unl

    nvd.nist.gov

References