CVE-2026-39987 Details
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.
A pre-authentication remote code execution vulnerability exists in Marimo versions through 0.20.4. The issue arises in the WebSocket terminal endpoint '/terminal/ws', which lacks proper authentication validation. This oversight allows an unauthenticated attacker to gain a full pseudo-terminal shell and execute arbitrary system commands. In contrast to other WebSocket endpoints that correctly validate authentication, the '/terminal/ws' endpoint only considers the running mode and platform compatibility before accepting connections, entirely bypassing authentication checks.
Users are advised to update to Marimo version 0.23.0 or later, where this vulnerability has been patched.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 23, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39987 | CISA-ADP | US Government Resource |
| https://www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hours | CISA-ADP | ExploitThird Party Advisory |
| https://github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12a | [email protected] | Patch |
| https://github.com/marimo-team/marimo/pull/9098 | [email protected] | Issue TrackingPatch |
| https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc | [email protected] | ExploitMitigationVendor Advisory |
This CVE is in CISA's Known Exploited Vulnerabilities Catalog
Reference CISA's BOD 22-01 and Known Exploited Vulnerabilities Catalog for further guidance and requirements.
| Vulnerability Name | Date Added | Due Date | Required Action |
|---|---|---|---|
| Marimo Remote Code Execution Vulnerability | Apr 23, 2026 | 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. |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-306 | Missing Authentication for Critical Function | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| coreweave marimo | < 0.23.0 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 23, 2026 | Initial Analysis | [email protected] |
| Apr 23, 2026 | CVE Modified | CISA-ADP |
| Apr 23, 2026 | CVE Modified | CISA-ADP |
| Apr 9, 2026 | New CVE Received | [email protected] |