Admidio: Reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion_CVE-2026-41661

{
    "lastseen": "",
    "description": "Admidio is an open-source user management solution. Prior to version 5.0.9, an unauthenticated attacker can execute arbitrary JavaScript in any Admidio user's browser through a reflected XSS in system/msg_window.php. The endpoint passes user input through htmlspecialchars(), which does not encode square brackets. A subsequent call to Language::prepareTextPlaceholders() converts those brackets into HTML angle brackets, producing executable markup. This issue has been patched in version 5.0.9.",
    "published": "2026-05-07T02:59:34.649Z",
    "modified": "2026-05-07T02:59:34.649Z",
    "type": "cve",
    "title": "Admidio: Reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion",
    "source": "GitHub_M",
    "references": "https://github.com/Admidio/admidio/security/advisories/GHSA-gq27-fc8w-vcmp\nhttps://github.com/Admidio/admidio/releases/tag/v5.0.9",
    "id": "CVE-2026-41661",
    "bulletinFamily": "",
    "cwe": [
        "CWE-79"
    ],
    "cvelist": null,
    "sourceData": "Admidio admidio < 5.0.9",
    "sourceHref": "",
    "cvss": {
        "score": 6.1,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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": "admidio",
    "version": "< 5.0.9",
    "vendor": "Admidio",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}