MaxSite CMS 0.94 through 109.6 HTML Upload XSS via admin_page

Advisories

MaxSite CMS 0.94 through 109.6 HTML Upload XSS via admin_page

severity: medium
date: 9/9/2026
Affecting: MaxSite CMS >= 0.94, <= 109.6
CVE: CVE-2026-87928
CWE: CWE-434 Unrestricted Upload of File with Dangerous Type
CVSS: 5.1
CVSS V4 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
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
Credit: EVIL0RD
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.

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