CVE-2026-39980: Citeum Opencti

High severity, CVSS 7.2. EPSS: 0.7% chance of exploitation in the next 30 days.

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 6.9.5, the safeEjs.ts file does not properly sanitize EJS templates. Users with the Manage customization capability can run arbitrary JavaScript in the context of the OpenCTI platform process during notifier template execution. This vulnerability is fixed in 6.9.5.

Affected products

• Citeum Opencti: before 6.9.5 (fixed in 6.9.5)

Published 2026-04-09. Last modified 2026-06-17.