Vulnerability in Citeum Opencti
CVE-2026-39980
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.013 (70.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 70.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.013 · change: +0.008
Affected products
- Citeum Opencti
- Opencti-Platform Opencti — versions < 6.9.5
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-jv9r-jw2f-rhrf (Vendor Advisory)
- github.com/OpenCTI-Platform/opencti/releases/tag/6.9.5 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-39980?
- CVE-2026-39980 is a critical-severity vulnerability in Citeum Opencti, classified under Improper Neutralization of Special Elements Used in a Template Engine. CVSS score: 9.1/10. Published 2026-04-09.
- How severe is CVE-2026-39980?
- Critical severity. CVSS v3 base score is 9.1 out of 10.
- Is CVE-2026-39980 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.