HtmlSanitizer has a bypass via template tag_CVE-2026-25543

{
    "lastseen": "",
    "description": "HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its contents are not sanitized. The template tag is a special tag that does not usually render its contents, unless the shadowrootmode attribute is set to open or closed. This issue has been patched in versions 9.0.892 and 9.1.893-beta.",
    "published": "2026-02-04T21:45:25.665Z",
    "modified": "2026-02-04T21:45:25.665Z",
    "type": "cve",
    "title": "HtmlSanitizer has a bypass via template tag",
    "source": "GitHub_M",
    "references": "https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-j92c-7v7g-gj3f\nhttps://github.com/mganss/HtmlSanitizer/commit/0ac53dca30ddad963f2b243669a5066933d82b81\nhttps://www.nuget.org/packages/HtmlSanitizer/9.0.892\nhttps://www.nuget.org/packages/HtmlSanitizer/9.1.893-beta",
    "id": "CVE-2026-25543",
    "bulletinFamily": "",
    "cwe": [
        "CWE-116"
    ],
    "cvelist": null,
    "sourceData": "mganss HtmlSanitizer < 9.0.892\nmganss HtmlSanitizer < 9.1.893-beta",
    "sourceHref": "",
    "cvss": {
        "score": 6.3,
        "severity": "MEDIUM",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
        "version": "4.0"
    },
    "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": "HtmlSanitizer",
    "version": "< 9.0.892",
    "vendor": "mganss",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}