Vulnerability-Lookup

GHSA-GJ33-HWGC-V3V8

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-05-27 15:33

Details

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]

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{
  "affected": [],
  "aliases": [
    "CVE-2026-46076"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:17:28Z",
    "severity": null
  },
  "details": "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": "GHSA-gj33-hwgc-v3v8",
  "modified": "2026-05-27T15:33:23Z",
  "published": "2026-05-27T15:33:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46076"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/009c0f726abeaa67aad1d96b883bdce01d405ce2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5fb4a5f361565f5b629d8a8fe5288ce8463c5727"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/924d721fae95687acedbaf624a094ed0e8b67104"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c36991c6f8d2ab56ee67aff04e3c357f45cfc76c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-46076 (GCVE-0-2026-46076)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:58 – Updated: 2026-05-27 12:58

Title

KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1

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]

Severity

No CVSS data available.

Assigner

Linux

References

4 references

URL	Tags
https://git.kernel.org/stable/c/924d721fae95687ac…
https://git.kernel.org/stable/c/009c0f726abeaa67a…
https://git.kernel.org/stable/c/5fb4a5f361565f5b6…
https://git.kernel.org/stable/c/c36991c6f8d2ab56e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 , < 924d721fae95687acedbaf624a094ed0e8b67104 (git) Affected: 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 , < 009c0f726abeaa67aad1d96b883bdce01d405ce2 (git) Affected: 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 , < 5fb4a5f361565f5b629d8a8fe5288ce8463c5727 (git) Affected: 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 , < c36991c6f8d2ab56ee67aff04e3c357f45cfc76c (git)
Linux	Linux	Affected: 6.2 Unaffected: 0 , < 6.2 (semver) Unaffected: 6.12.86 , ≤ 6.12.* (semver) Unaffected: 6.18.27 , ≤ 6.18.* (semver) Unaffected: 7.0.4 , ≤ 7.0.* (semver) Unaffected: 7.1-rc1 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/hyperv.h",
            "arch/x86/kvm/svm/hyperv.h",
            "arch/x86/kvm/svm/nested.c",
            "arch/x86/kvm/svm/svm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "924d721fae95687acedbaf624a094ed0e8b67104",
              "status": "affected",
              "version": "3f4a812edf5cb0a50e65fbdfafdb3e688da18f16",
              "versionType": "git"
            },
            {
              "lessThan": "009c0f726abeaa67aad1d96b883bdce01d405ce2",
              "status": "affected",
              "version": "3f4a812edf5cb0a50e65fbdfafdb3e688da18f16",
              "versionType": "git"
            },
            {
              "lessThan": "5fb4a5f361565f5b629d8a8fe5288ce8463c5727",
              "status": "affected",
              "version": "3f4a812edf5cb0a50e65fbdfafdb3e688da18f16",
              "versionType": "git"
            },
            {
              "lessThan": "c36991c6f8d2ab56ee67aff04e3c357f45cfc76c",
              "status": "affected",
              "version": "3f4a812edf5cb0a50e65fbdfafdb3e688da18f16",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/hyperv.h",
            "arch/x86/kvm/svm/hyperv.h",
            "arch/x86/kvm/svm/nested.c",
            "arch/x86/kvm/svm/svm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.2"
            },
            {
              "lessThan": "6.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.86",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.27",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.86",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.27",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.4",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1-rc1",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:58:09.169Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/924d721fae95687acedbaf624a094ed0e8b67104"
        },
        {
          "url": "https://git.kernel.org/stable/c/009c0f726abeaa67aad1d96b883bdce01d405ce2"
        },
        {
          "url": "https://git.kernel.org/stable/c/5fb4a5f361565f5b629d8a8fe5288ce8463c5727"
        },
        {
          "url": "https://git.kernel.org/stable/c/c36991c6f8d2ab56ee67aff04e3c357f45cfc76c"
        }
      ],
      "title": "KVM: nSVM: Raise #UD if unhandled VMMCALL isn\u0027t intercepted by L1",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46076",
    "datePublished": "2026-05-27T12:58:09.169Z",
    "dateReserved": "2026-05-13T15:03:33.096Z",
    "dateUpdated": "2026-05-27T12:58:09.169Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-GJ33-HWGC-V3V8

CVE-2026-46076 (GCVE-0-2026-46076)

Tags

Sightings

Nomenclature