{
    "id": "CVE-2019-9791",
    "published": "2019-04-26 17:29:01",
    "last_modified": "2026-06-17 02:44:21",
    "cvss_score": "9.8",
    "cvss_severity": "CRITICAL",
    "cvss_version": "3.1",
    "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
    "cwe": "CWE-843",
    "description": "The type inference system allows the compilation of functions that can cause type confusions between arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor function is entered through on-stack replacement (OSR). This allows for possible arbitrary reading and writing of objects during an exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.",
    "epss_score": "0.19915",
    "epss_percentile": "0.97346",
    "kev": 0,
    "kev_due": null,
    "has_exploit": 1,
    "updated_at": "2026-09-27 18:17:24",
    "priority": {
        "rank": 2,
        "label": "Patch early",
        "why": "A public exploit exists."
    },
    "products": [
        {
            "vendor": "mozilla",
            "product": "firefox"
        },
        {
            "vendor": "mozilla",
            "product": "thunderbird"
        },
        {
            "vendor": "redhat",
            "product": "enterprise_linux"
        },
        {
            "vendor": "redhat",
            "product": "enterprise_linux_eus"
        },
        {
            "vendor": "redhat",
            "product": "enterprise_linux_server_aus"
        },
        {
            "vendor": "redhat",
            "product": "enterprise_linux_server_tus"
        }
    ],
    "kev_detail": null,
    "exploits": [
        {
            "source": "exploit-db",
            "ref_id": "46613",
            "title": "Spidermonkey - IonMonkey Type Inference is Incorrect for Constructors Entered via OSR",
            "date": "2019-03-26",
            "url": "https://www.exploit-db.com/exploits/46613"
        }
    ],
    "refs_list": [
        "https://access.redhat.com/errata/RHSA-2019:0966",
        "https://access.redhat.com/errata/RHSA-2019:1144",
        "https://bugzilla.mozilla.org/show_bug.cgi?id=1530958",
        "https://www.mozilla.org/security/advisories/mfsa2019-07/",
        "https://www.mozilla.org/security/advisories/mfsa2019-08/",
        "https://www.mozilla.org/security/advisories/mfsa2019-11/",
        "https://access.redhat.com/errata/RHSA-2019:0966",
        "https://access.redhat.com/errata/RHSA-2019:1144",
        "https://bugzilla.mozilla.org/show_bug.cgi?id=1530958",
        "https://www.mozilla.org/security/advisories/mfsa2019-07/",
        "https://www.mozilla.org/security/advisories/mfsa2019-08/",
        "https://www.mozilla.org/security/advisories/mfsa2019-11/"
    ]
}