Arbitrary file upload in Maxsite Cms
CVE-2026-87928
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.
Vulnerability class: Unrestricted File Upload
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (21.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 21.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/maxsite/cms (product)
- github.com/EviL0rd/maxsite-cve2/blob/main/2026.09.08-maxsite-cms-arbitrary-file… (technical-description, exploit)
- github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/applicatio… (technical-description)
- www.vulncheck.com/advisories/maxsite-cms-0.94-through-109.6-html-upload-xss-via… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-87928?
- CVE-2026-87928 is a medium-severity vulnerability in Maxsite Cms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 5.4/10. Published 2026-09-09.
- How severe is CVE-2026-87928?
- Medium severity. CVSS v3 base score is 5.4 out of 10.