What is CVE-2026-7429?

CVE-2026-7429 is a medium-severity vulnerability in Siteserver Sscms, classified under Cross-site Scripting. CVSS score: 4.6/10. Published 2026-04-30.

How severe is CVE-2026-7429?

Medium severity. CVSS v3 base score is 4.6 out of 10.

XSS in Siteserver Sscms

CVE-2026-7429

SSCMS v7.4.0 contains a reflected cross-site scripting vulnerability in the STL processing endpoint that allows attackers to execute arbitrary JavaScript by crafting malicious STL template payloads that are decrypted and returned without proper sanitization. Attackers can exploit improper output encoding in the /api/stl/actions/dynamic endpoint to inject executable JavaScript into JSON responses, leading to session hijacking, phishing attacks, and unauthorized actions performed on behalf of users.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-04-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (19.5th percentile), scored 2026-10-06.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 19.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Siteserver Sscms — versions 7.4.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/siteserver/cms/issues/3892 (issue-tracking)
github.com/siteserver/cms (product)
www.vulncheck.com/advisories/sscms-reflected-cross-site-scripting-via-stl-proce… (third-party-advisory)

Frequently asked questions

What is CVE-2026-7429?: CVE-2026-7429 is a medium-severity vulnerability in Siteserver Sscms, classified under Cross-site Scripting. CVSS score: 4.6/10. Published 2026-04-30.
How severe is CVE-2026-7429?: Medium severity. CVSS v3 base score is 4.6 out of 10.