DOMPurify: Prototype Pollution to XSS Bypass via CUSTOM_ELEMENT_HANDLING Fallback_CVE-2026-41238

{
    "lastseen": "",
    "description": "DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions 3.0.1 through 3.3.3 are vulnerable to a prototype pollution-based XSS bypass. When an application uses `DOMPurify.sanitize()` with the default configuration (no `CUSTOM_ELEMENT_HANDLING` option), a prior prototype pollution gadget can inject permissive `tagNameCheck` and `attributeNameCheck` regex values into `Object.prototype`, causing DOMPurify to allow arbitrary custom elements with arbitrary attributes \u2014 including event handlers \u2014 through sanitization. Version 3.4.0 fixes the issue.",
    "published": "2026-04-23T14:43:17.730Z",
    "modified": "2026-04-23T14:43:17.730Z",
    "type": "cve",
    "title": "DOMPurify: Prototype Pollution to XSS Bypass via CUSTOM_ELEMENT_HANDLING Fallback",
    "source": "GitHub_M",
    "references": "https://github.com/cure53/DOMPurify/security/advisories/GHSA-v9jr-rg53-9pgp\nhttps://github.com/cure53/DOMPurify/releases/tag/3.4.0",
    "id": "CVE-2026-41238",
    "bulletinFamily": "",
    "cwe": [
        "CWE-79",
        "CWE-1321"
    ],
    "cvelist": null,
    "sourceData": "cure53 DOMPurify >= 3.0.1, < 3.4.0",
    "sourceHref": "",
    "cvss": {
        "score": 6.9,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/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": "DOMPurify",
    "version": ">= 3.0.1, < 3.4.0",
    "vendor": "cure53",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}