CVE-2025-26621: OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to version 6.5.2, any user with the capability…

PriorityP430medium6.8CVSS 3.1

AVNACLPRHUINSCCNINAH

EPSS

0.35%

27.2th percentile

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to version 6.5.2, any user with the capability manage customizations can edit webhook that will execute javascript code. This can be abused to cause a denial of service attack by prototype pollution, making the node js server running the OpenCTI frontend become unavailable. Version 6.5.2 fixes the issue.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
citeum	opencti	< 6.5.2	6.5.2
opencti-platform	opencti	< 6.5.2	6.5.2

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.