CVE-2026-39987marimo Affected by Pre-Auth Remote Code Execution via Terminal WebSocket Authentication Bypass
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.
Overview
Severity
| Score | Severity | Version | Vector String |
|---|---|---|---|
| 9.3 | CRITICAL | 4.0GitHub_M (CNA) | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| 9.8 | CRITICAL | 3.1NVD | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
CISA required action
⚡ Known exploited · remediation due May 7, 2026
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Details
- CVE ID
- CVE-2026-39987
- Status
- Analyzed
- Assigner (CNA)
- GitHub_M
- Published
- Apr 9, 2026
- Last modified
- 2026-06-17 10:42 UTC
- Weaknesses
- CWE-306 · Missing Authentication for Critical Function
Affected Products
As published by the CNA in the CVE record.
marimo-teammarimo1 version range
- < 0.23.0
References
- github.com https://github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12a
- github.com https://github.com/marimo-team/marimo/pull/9098
- github.com https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc
- cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39987
- sysdig.com https://www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hours