RCE in Citeum Opencti

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 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.

Vulnerability class: RCE (Remote Code Execution)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:H.

EPSS exploit prediction

EPSS: 0.004 (35.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-26621: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-26621?
CVE-2025-26621 is a high-severity vulnerability in Citeum Opencti, classified under Code Injection. CVSS score: 7.6/10. Published 2025-05-19.
How severe is CVE-2025-26621?
High severity. CVSS v3 base score is 7.6 out of 10.