XSS in Citeum Opencti

CVE-2026-35212

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Versions prior to 7.260227.0 are vulnerable to XSS in the rendering of email-message observable body data. The content of the body field isn't appropriately sanitized when being rendered. Does require user interaction but could be exploited by someone sharing stix or any of the ingester. This could lead to CSRF and then large scale session theft. Version 7.260227.0 contains a fix.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (15.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 15.9% 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-2026-35212: held from 0.001 to 0.003.

EPSS over last 30 days · oldest: 0.001 · newest: 0.003 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-35212?
CVE-2026-35212 is a medium-severity vulnerability in Citeum Opencti, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-06-02.
How severe is CVE-2026-35212?
Medium severity. CVSS v3 base score is 6.1 out of 10.