github - ghsa-3fcf-v62x-cm7w

GHSA-3FCF-V62X-CM7W

Vulnerability from github – Published: 2025-12-30 15:30 – Updated: 2025-12-30 15:30

Details

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

x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction

On hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs with ConfigVersion 9.3 or later support IBT in the guest. However, current versions of Hyper-V have a bug in that there's not an ENDBR64 instruction at the beginning of the hypercall page. Since hypercalls are made with an indirect call to the hypercall page, all hypercall attempts fail with an exception and Linux panics.

A Hyper-V fix is in progress to add ENDBR64. But guard against the Linux panic by clearing X86_FEATURE_IBT if the hypercall page doesn't start with ENDBR. The VM will boot and run without IBT.

If future Linux 32-bit kernels were to support IBT, additional hypercall page hackery would be needed to make IBT work for such kernels in a Hyper-V VM.

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{
  "affected": [],
  "aliases": [
    "CVE-2023-54172"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-30T13:16:05Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction\n\nOn hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs\nwith ConfigVersion 9.3 or later support IBT in the guest. However,\ncurrent versions of Hyper-V have a bug in that there\u0027s not an ENDBR64\ninstruction at the beginning of the hypercall page. Since hypercalls are\nmade with an indirect call to the hypercall page, all hypercall attempts\nfail with an exception and Linux panics.\n\nA Hyper-V fix is in progress to add ENDBR64. But guard against the Linux\npanic by clearing X86_FEATURE_IBT if the hypercall page doesn\u0027t start\nwith ENDBR. The VM will boot and run without IBT.\n\nIf future Linux 32-bit kernels were to support IBT, additional hypercall\npage hackery would be needed to make IBT work for such kernels in a\nHyper-V VM.",
  "id": "GHSA-3fcf-v62x-cm7w",
  "modified": "2025-12-30T15:30:30Z",
  "published": "2025-12-30T15:30:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-54172"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/73626b70b361ddda7c380e52c236aa4f2487c402"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/98cccbd0a19a161971bc7f7feb10577adc62c400"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d5ace2a776442d80674eff9ed42e737f7dd95056"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2023-54172 (GCVE-0-2023-54172)

Vulnerability from cvelistv5 – Published: 2025-12-30 12:08 – Updated: 2025-12-30 12:08

Title

x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction

Summary

In the Linux kernel, the following vulnerability has been resolved: x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction On hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs with ConfigVersion 9.3 or later support IBT in the guest. However, current versions of Hyper-V have a bug in that there's not an ENDBR64 instruction at the beginning of the hypercall page. Since hypercalls are made with an indirect call to the hypercall page, all hypercall attempts fail with an exception and Linux panics. A Hyper-V fix is in progress to add ENDBR64. But guard against the Linux panic by clearing X86_FEATURE_IBT if the hypercall page doesn't start with ENDBR. The VM will boot and run without IBT. If future Linux 32-bit kernels were to support IBT, additional hypercall page hackery would be needed to make IBT work for such kernels in a Hyper-V VM.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/98cccbd0a19a16197…
	https://git.kernel.org/stable/c/73626b70b361ddda7…
	https://git.kernel.org/stable/c/d5ace2a776442d806…

Impacted products

Vendor

Product

Version

Linux

Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 98cccbd0a19a161971bc7f7feb10577adc62c400 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 73626b70b361ddda7c380e52c236aa4f2487c402 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d5ace2a776442d80674eff9ed42e737f7dd95056 (git)

Linux

Unaffected: 6.1.45 , ≤ 6.1.* (semver)
Unaffected: 6.4.10 , ≤ 6.4.* (semver)
Unaffected: 6.5 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/hyperv/hv_init.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "98cccbd0a19a161971bc7f7feb10577adc62c400",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "73626b70b361ddda7c380e52c236aa4f2487c402",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "d5ace2a776442d80674eff9ed42e737f7dd95056",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/hyperv/hv_init.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.4.*",
              "status": "unaffected",
              "version": "6.4.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.45",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.4.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.5",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction\n\nOn hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs\nwith ConfigVersion 9.3 or later support IBT in the guest. However,\ncurrent versions of Hyper-V have a bug in that there\u0027s not an ENDBR64\ninstruction at the beginning of the hypercall page. Since hypercalls are\nmade with an indirect call to the hypercall page, all hypercall attempts\nfail with an exception and Linux panics.\n\nA Hyper-V fix is in progress to add ENDBR64. But guard against the Linux\npanic by clearing X86_FEATURE_IBT if the hypercall page doesn\u0027t start\nwith ENDBR. The VM will boot and run without IBT.\n\nIf future Linux 32-bit kernels were to support IBT, additional hypercall\npage hackery would be needed to make IBT work for such kernels in a\nHyper-V VM."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-30T12:08:46.146Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/98cccbd0a19a161971bc7f7feb10577adc62c400"
        },
        {
          "url": "https://git.kernel.org/stable/c/73626b70b361ddda7c380e52c236aa4f2487c402"
        },
        {
          "url": "https://git.kernel.org/stable/c/d5ace2a776442d80674eff9ed42e737f7dd95056"
        }
      ],
      "title": "x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-54172",
    "datePublished": "2025-12-30T12:08:46.146Z",
    "dateReserved": "2025-12-30T12:06:44.496Z",
    "dateUpdated": "2025-12-30T12:08:46.146Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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-3FCF-V62X-CM7W

CVE-2023-54172 (GCVE-0-2023-54172)

Tags

Sightings

Nomenclature