Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component_CVE-2026-8959

{
    "lastseen": "",
    "description": "Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.",
    "published": "2026-05-19T12:29:55.560Z",
    "modified": "2026-05-19T16:08:39.887Z",
    "type": "cve",
    "title": "Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component",
    "source": "mozilla",
    "references": "https://bugzilla.mozilla.org/show_bug.cgi?id=2034754\nhttps://www.mozilla.org/security/advisories/mfsa2026-46/\nhttps://www.mozilla.org/security/advisories/mfsa2026-48/",
    "id": "CVE-2026-8959",
    "bulletinFamily": "",
    "cwe": [
        "CWE-119",
        "CWE-20",
        "CWE-693"
    ],
    "cvelist": null,
    "sourceData": "",
    "sourceHref": "",
    "cvss": {
        "score": 9.6,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
        "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": "Firefox",
    "version": "140.11",
    "vendor": "Mozilla",
    "ai_description": "Sandbox escape vulnerability due to incorrect boundary conditions in the Widget: Win32 component",
    "ai_severity": "Critical",
    "ai_vendor": "Mozilla Foundation",
    "ai_product": "Firefox",
    "ai_version": "140.11, 151",
    "ai_score": 9.6
}