CVE-2026-7429: SSCMS v7.4.0 Reflected Cross-Site Scripting via STL Processing

Severity: medium (CVSS 4.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-30 · updated 2026-10-26
Weakness: CWE-79

Description

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.

Affected products

siteserver SSCMS: 7.4.0

References

https://github.com/siteserver/cms
https://github.com/siteserver/cms/issues/3892
https://www.vulncheck.com/advisories/sscms-reflected-cross-site-scripting-via-stl-processing
https://github.com/siteserver/cms/issues/3892

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