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CVE-2026-39980

Critical

Description

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.

SeverityCritical
CVSS9.1
Exploit probability—
ProductCiteum Opencti
PublishedApr 9, 2026
First seenApr 9, 2026
Weakness typeCWE-1336CWE-1336

How to fix

Update
  • citeum opencti6.9.5 or later
  • pycti6.9.5 or later

Affected products

ProductAffected versionsFixed in
citeum openctiv < 6.9.56.9.5
pyctiPyPIv < 6.9.56.9.5

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