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
- 99.56% probability · 100th percentile
- Public exploits
- 1 in Exploit-DB · first 2 September 2026
- CISA KEV
- Listed 23 April 2026 · due 7 May 2026
- Weakness
- CWE-306
- Affected
- coreweave/marimo
- Source
- security-advisories@github.com
EPSS moved from 37.9% on 24 September 2026 to 99.6% on 30 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
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
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
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, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.