CVE-2025-26621

Name: CVE-2025-26621
Creator: NVD / NIST
Published: 2025-05-19T16:15:28.56+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.8/10EPSS 0.35%

Last modified Jun 17, 2026

CVE-2025-26621 is a medium-severity vulnerability rated 6.8/10 on the CVSS scale. 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. EPSS estimates a 0.35% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

6.8/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H

EPSS Probability

0.35%

27.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Citeum	Opencti	< 6.5.2

References

https://github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-gq63-jm3h-374pVendor Advisory
https://github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-mf88-g2wq-p7qmNot Applicable

Timeline

Published: May 19, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-26621?

How severe is CVE-2025-26621?

CVE-2025-26621 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.35% probability of exploitation in the next 30 days.

How do I fix CVE-2025-26621?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-26621?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST