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GHSA-4PVM-QH3Q-CCRF

Vulnerability from github – Published: 2026-11-03 12:31 – Updated: 2026-11-03 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()

hv_apicid_to_vp_index() currently uses the per-cpu hypercall input and output pages. This function is called when running in VTL2 and when running in an SEV-SNP CoCo VM with no paravisor. In the former case, the output page is allocated, but in the latter case it is not, so the hypervisor stores the output VP index in memory that has not been allocated by the guest.

Fix this by using the input page for both input and output. The hypercall has very small input and output, so sharing the same page for both is straightforward. An alternative fix is to allocate the per-cpu output page when running in an SEV-SNP CoCo guest, but this uses significantly more memory, particularly with larger vCPUs counts.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-99258"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-11-03T12:17:32Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()\n\nhv_apicid_to_vp_index() currently uses the per-cpu hypercall input\nand output pages. This function is called when running in VTL2 and\nwhen running in an SEV-SNP CoCo VM with no paravisor. In the former\ncase, the output page is allocated, but in the latter case it is\nnot, so the hypervisor stores the output VP index in memory that has\nnot been allocated by the guest.\n\nFix this by using the input page for both input and output. The\nhypercall has very small input and output, so sharing the same\npage for both is straightforward. An alternative fix is to\nallocate the per-cpu output page when running in an SEV-SNP CoCo\nguest, but this uses significantly more memory, particularly\nwith larger vCPUs counts.",
  "id": "GHSA-4pvm-qh3q-ccrf",
  "modified": "2026-11-03T12:31:50Z",
  "published": "2026-11-03T12:31:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99258"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b561786c9076a892ef8b8f416c9828bc87ed44f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7b74c117e2aac78e0f723e1c9c3644451c56b0d9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bdba5f1b8bd0d18b1df61f769b559ed272902489"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-99258 (GCVE-0-2026-99258)

Vulnerability from cvelistv5 – Published: 2026-11-03 11:25 – Updated: 2026-11-03 11:40

Title

x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()

Summary

In the Linux kernel, the following vulnerability has been resolved: x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index() hv_apicid_to_vp_index() currently uses the per-cpu hypercall input and output pages. This function is called when running in VTL2 and when running in an SEV-SNP CoCo VM with no paravisor. In the former case, the output page is allocated, but in the latter case it is not, so the hypervisor stores the output VP index in memory that has not been allocated by the guest. Fix this by using the input page for both input and output. The hypercall has very small input and output, so sharing the same page for both is straightforward. An alternative fix is to allocate the per-cpu output page when running in an SEV-SNP CoCo guest, but this uses significantly more memory, particularly with larger vCPUs counts.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6637 records in the last 180 days details

References

4 references

URL	Tags
https://git.kernel.org/stable/c/bdba5f1b8bd0d18b1…
https://git.kernel.org/stable/c/2b561786c9076a892…
https://git.kernel.org/stable/c/bc8ca0f4769627ae7…
https://git.kernel.org/stable/c/7b74c117e2aac78e0…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 3d12349ade541eefde0e71bf5c4aa7aa04c52a79 , < bdba5f1b8bd0d18b1df61f769b559ed272902489 (git) Affected: 86c48271e0d60c82665e9fd61277002391efcef7 , < 2b561786c9076a892ef8b8f416c9828bc87ed44f (git) Affected: 86c48271e0d60c82665e9fd61277002391efcef7 , < bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9 (git) Affected: 86c48271e0d60c82665e9fd61277002391efcef7 , < 7b74c117e2aac78e0f723e1c9c3644451c56b0d9 (git) Affected: cb002d6c8f06d6061e84b2109cb84416107a9fb9 (git) Affected: 6.12.41 , < 6.12.115 (semver) Affected: 6.15.3 , < 6.16 (semver)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.12.115 , ≤ 6.12.* (semver) Unaffected: 6.18.59 , ≤ 6.18.* (semver) Unaffected: 7.2.13 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/hyperv/hv_init.c"
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              "versionType": "git"
            },
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              "version": "6.12.41",
              "versionType": "semver"
            },
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              "version": "6.15.3",
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            }
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              "versionType": "semver"
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            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
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            {
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              "status": "unaffected",
              "version": "7.2.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
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        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-03T11:40:46.409Z",
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      "title": "x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()",
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    "datePublished": "2026-11-03T11:25:14.680Z",
    "dateReserved": "2026-09-25T10:25:14.404Z",
    "dateUpdated": "2026-11-03T11:40:46.409Z",
    "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.

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