CVE-2026-39987
Marimo Remote Code Execution Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 7 May 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 4.0
- 9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 98.95% probability · 100th percentile
- CISA KEV
- Listed 23 April 2026 · due 7 May 2026
- Weakness
- CWE-306
- Affected
- coreweave/marimo
- Source
- security-advisories@github.com
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc ; https://nvd.nist.gov/vuln/detail/CVE-2026-39987
References
- https://github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12aPatch
- https://github.com/marimo-team/marimo/pull/9098Issue Tracking, Patch
- https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xcExploit, Mitigation, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39987US Government Resource
- https://www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hoursExploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.