HAX CMS PHP Has a Stored XSS via Case-Sensitivity Mismatch in HTML Upload Validation_CVE-2026-46392

{
    "lastseen": "",
    "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": "2026-06-05T18:20:25.658Z",
    "modified": "2026-06-05T18:20:25.658Z",
    "type": "cve",
    "title": "HAX CMS PHP Has a Stored XSS via Case-Sensitivity Mismatch in HTML Upload Validation",
    "source": "GitHub_M",
    "references": "https://github.com/haxtheweb/issues/security/advisories/GHSA-hg33-w4j2-95qp",
    "id": "CVE-2026-46392",
    "bulletinFamily": "",
    "cwe": [
        "CWE-178",
        "CWE-434"
    ],
    "cvelist": null,
    "sourceData": "haxtheweb haxcms-php < 26.0.0",
    "sourceHref": "",
    "cvss": {
        "score": 8.7,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "haxcms-php",
    "version": "< 26.0.0",
    "vendor": "haxtheweb",
    "ai_description": "Stored XSS via case-sensitivity mismatch in HTML upload validation",
    "ai_severity": "High",
    "ai_vendor": "haxtheweb",
    "ai_product": "HAX CMS PHP",
    "ai_version": "< 26.0.0",
    "ai_score": 8.7
}