KVM: nSVM: Raise #UD if unhandled VMMCALL isn’t intercepted by L1_CVE-2026-46076

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1\n\nExplicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want\nto intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the\nhypercall is something other than one of the supported Hyper-V hypercalls.\nWhen all of the above conditions are met, KVM will intercept VMMCALL but\nnever forward it to L1, i.e. will let L2 make hypercalls as if it were L1.\n\nThe TLFS says a whole lot of nothing about this scenario, so go with the\narchitectural behavior, which says that VMMCALL #UDs if it's not\nintercepted.\n\nOpportunistically do a 2-for-1 stub trade by stub-ifying the new API\ninstead of the helpers it uses.  The last remaining \"single\" stub will\nsoon be dropped as well.\n\n[sean: rewrite changelog and comment, tag for stable, remove defunct stubs]",
    "published": "2026-05-27T12:58:09.169Z",
    "modified": "2026-05-30T10:47:16.875Z",
    "type": "cve",
    "title": "KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/924d721fae95687acedbaf624a094ed0e8b67104\nhttps://git.kernel.org/stable/c/009c0f726abeaa67aad1d96b883bdce01d405ce2\nhttps://git.kernel.org/stable/c/5fb4a5f361565f5b629d8a8fe5288ce8463c5727\nhttps://git.kernel.org/stable/c/c36991c6f8d2ab56ee67aff04e3c357f45cfc76c",
    "id": "CVE-2026-46076",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16\nLinux Linux 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16\nLinux Linux 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16\nLinux Linux 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16\nLinux Linux 6.2",
    "sourceHref": "",
    "cvss": {
        "score": 7.9,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
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            "privilegesRequired": "",
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            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "3f4a812edf5cb0a50e65fbdfafdb3e688da18f16",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
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    "ai_score": 0
}