MSRXCVE-2026-39987
CVE-2026-39987
Marimo Remote Code Execution Vulnerability
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CVSS 4.0 · CNA · github.com
chance of exploitation in the next 30 days (EPSS; in the top 1% of all CVEs)
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.
Scores
Affected packages and fixed versions
| Package | Ecosystem | Fixed in |
|---|---|---|
| marimo | PyPI | 0.23.0 |
Affected products
- coreweave marimo: < 0.23.0
Weakness: CWE-306
Also known as: GHSA-2679-6mx9-h9xc, PYSEC-2026-407
5 references (advisories, patches, write-ups)
- 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: NVD, CVE.org, OSV.dev, FIRST EPSS. Missing ones did not answer or have no record yet.