Description
HAX CMS helps manage microsite universe with PHP or NodeJs backends. Prior to version 26.0.0 of HAX CMS PHP, the `saveFile` endpoint validates upload extensions case-insensitively and writes the filename to disk verbatim, but the `.htaccess` rule that forces `Content-Disposition: attachment` on HTML files is case-sensitive. An HTML file uploaded with an uppercase extension (`.HTML`, `.Html`, `.HTM`) is still served as `text/html` but the forced-download header never applies, so the browser renders it inline and executes any embedded JavaScript in the HAXcms origin. This bypasses the mitigation shipped for CVE-2026-22704. Version 26.0.0 contains a fix.
Published: 2026-06-05
Score: 8.7 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Fri, 05 Jun 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 05 Jun 2026 19:00:00 +0000

Type Values Removed Values Added
Description HAX CMS helps manage microsite universe with PHP or NodeJs backends. Prior to version 26.0.0 of HAX CMS PHP, the `saveFile` endpoint validates upload extensions case-insensitively and writes the filename to disk verbatim, but the `.htaccess` rule that forces `Content-Disposition: attachment` on HTML files is case-sensitive. An HTML file uploaded with an uppercase extension (`.HTML`, `.Html`, `.HTM`) is still served as `text/html` but the forced-download header never applies, so the browser renders it inline and executes any embedded JavaScript in the HAXcms origin. This bypasses the mitigation shipped for CVE-2026-22704. Version 26.0.0 contains a fix.
Title HAX CMS PHP Has a Stored XSS via Case-Sensitivity Mismatch in HTML Upload Validation
Weaknesses CWE-178
CWE-434
References
Metrics cvssV3_1

{'score': 8.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-05T19:11:31.488Z

Reserved: 2026-05-13T19:53:47.922Z

Link: CVE-2026-46392

cve-icon Vulnrichment

Updated: 2026-06-05T19:11:11.675Z

cve-icon NVD

Status : Deferred

Published: 2026-06-05T19:16:33.160

Modified: 2026-06-05T20:17:33.480

Link: CVE-2026-46392

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses