FKIE_CVE-2026-46076

Vulnerability from fkie_nvd - Published: 2026-05-27 14:17 - Updated: 2026-05-27 14:48
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1 Explicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want to intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the hypercall is something other than one of the supported Hyper-V hypercalls. When all of the above conditions are met, KVM will intercept VMMCALL but never forward it to L1, i.e. will let L2 make hypercalls as if it were L1. The TLFS says a whole lot of nothing about this scenario, so go with the architectural behavior, which says that VMMCALL #UDs if it's not intercepted. Opportunistically do a 2-for-1 stub trade by stub-ifying the new API instead of the helpers it uses. The last remaining "single" stub will soon be dropped as well. [sean: rewrite changelog and comment, tag for stable, remove defunct stubs]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/009c0f726abeaa67aad1d96b883bdce01d405ce2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5fb4a5f361565f5b629d8a8fe5288ce8463c5727
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/924d721fae95687acedbaf624a094ed0e8b67104
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c36991c6f8d2ab56ee67aff04e3c357f45cfc76c
Impacted products
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Raise #UD if unhandled VMMCALL isn\u0027t 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\u0027s 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]"
    }
  ],
  "id": "CVE-2026-46076",
  "lastModified": "2026-05-27T14:48:03.013",
  "metrics": {},
  "published": "2026-05-27T14:17:28.930",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/009c0f726abeaa67aad1d96b883bdce01d405ce2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5fb4a5f361565f5b629d8a8fe5288ce8463c5727"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/924d721fae95687acedbaf624a094ed0e8b67104"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c36991c6f8d2ab56ee67aff04e3c357f45cfc76c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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