Vulnerability
CVE-2026-39987
marimo: unauthenticated remote code execution
Most severe levelDEFCON 4 · Moderate risk
Official data
- CVSS 4.0
- 9.3 · critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-306
- EPSS
- 99.74% probability of exploitation in the next 30 days, higher than 99% of CVEs
- CISA KEV catalogue
- Yes, since 23 April 2026
Sources: NVD (CVSS, weakness, publication), FIRST (EPSS), CISA (KEV catalogue).
Data read on 4 November 2026.
Timeline
- 9 April 2026Published on NVD
- 10 April 2026First in the DefenceLevel briefing
- 23 April 2026Added to the CISA KEV catalogue
In DefenceLevel briefings4 days
- 3 September 2026New in the last 24 hoursDEFCON 4
- 30 May 2026Worth watching
- 24 April 2026New in the last 24 hoursDEFCON 4
- 10 April 2026New in the last 24 hoursDEFCON 4
Last 12 months.
The full analysis is in the briefingThe full analysis is in your archive
Why it matters now, who is affected and what to do: every day at 05:00 UTC, for subscribers.Why it matters, who is affected and what to do, as in the daily briefing.