CVEs / CVE-2026-39987
CVE-2026-39987: Marimo Remote Code Execution Vulnerability
- Known exploited in the CISA KEV catalog since 23 Apr 2026
- critical 9.8 CVSS 3.1 (NVD)
- EPSS 99.5% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Marimo contains an pre-authorization remote code execution vulnerability, allowing an unauthenticated attacked to shell access and execute arbitrary system commands.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| marimo-team marimo | < 0.23.0 | — |
| Product | Affected | Fixed in |
|---|---|---|
| marimo (PyPI) | before 0.23.0 | 0.23.0 |
Package versions from GHSA-2679-6mx9-h9xc.
Exploitation
| In CISA KEV since | 23 Apr 2026 |
|---|---|
| Due date for US federal agencies | 7 May 2026 |
| Used in ransomware campaigns | 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. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-306 |
References
- CVE-2026-39987 on NVD
- CVE-2026-39987 in the CISA KEV catalog
- https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc (cited by CISA)
- CVE-2026-39987 on OSV
- https://github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12a Patch
- https://github.com/marimo-team/marimo/pull/9098 Issue Tracking, Patch
- https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc Exploit, Mitigation, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39987 US Government Resource
- https://www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hours Exploit, Third Party Advisory
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.