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x86/mtrr: Check if fixed MTRRs exist before saving them

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: x86/mtrr: Check if fixed MTRRs exist before saving them MTRRs have an obsolete fixed variant for fine grained caching control of the 640K-1MB region that uses separate MSRs. This fixed variant has a separate capability bit in the MTRR capability MSR. So far all x86 CPUs which support MTRR have this separate bit set, so it went unnoticed that mtrr_save_state() does not check the capability bit before accessing the fixed MTRR MSRs. Though on a CPU that does not support the fixed MTRR capability this results in a #GP. The #GP itself is harmless because the RDMSR fault is handled gracefully, but results in a WARN_ON(). Add the missing capability check to prevent this.

Products
Kernel
Affected versions
Not specified
Fixed versions
4.19.320, 5.10.224, 5.15.165, 5.4.282, 6.1.105, 6.10.5, 6.6.46
CVEs
CVE-2024-44948
Confirmed fixed CVEs
Not specified
Updated in this feed
2 Nov 2026, 18:27 UTC · Revision 1

Source evidence

x86/mtrr: Check if fixed MTRRs exist before saving them

core-osv · Original source

Published 4 Sept 2024, 18:35 UTC

In the Linux kernel, the following vulnerability has been resolved: x86/mtrr: Check if fixed MTRRs exist before saving them MTRRs have an obsolete fixed variant for fine grained caching control of the 640K-1MB region that uses separate MSRs. This fixed variant has a separate capability bit in the MTRR capability MSR. So far all x86 CPUs which support MTRR have this separate bit set, so it went unnoticed that mtrr_save_state() does not check the capability bit before accessing the fixed MTRR MSRs. Though on a CPU that does not support the fixed MTRR capability this results in a #GP. The #GP itself is harmless because the RDMSR fault is handled gracefully, but results in a WARN_ON(). Add the missing capability check to prevent this.

osv:CVE-2024-44948

Kernel

Fixed versions: 4.19.320, 5.4.282, 5.10.224, 5.15.165, 6.1.105, 6.6.46, 6.10.5

Complete source record
{
  "id": "f3c409abb3cc6ac4f876af161521d53145bed5aaace078fe0a93d0a89036173b",
  "url": "https://osv.dev/vulnerability/CVE-2024-44948",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "x86/mtrr: Check if fixed MTRRs exist before saving them",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: x86/mtrr: Check if fixed MTRRs exist before saving them MTRRs have an obsolete fixed variant for fine grained caching control of the 640K-1MB region that uses separate MSRs. This fixed variant has a separate capability bit in the MTRR capability MSR. So far all x86 CPUs which support MTRR have this separate bit set, so it went unnoticed that mtrr_save_state() does not check the capability bit before accessing the fixed MTRR MSRs. Though on a CPU that does not support the fixed MTRR capability this results in a #GP. The #GP itself is harmless because the RDMSR fault is handled gracefully, but results in a WARN_ON(). Add the missing capability check to prevent this.",
    "evidence": "osv:CVE-2024-44948",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.19.320",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.4.282",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.224",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.165",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.105",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.46",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.10.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
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      "aliases": [
        "CVE-2024-44948"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
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                },
                {
                  "fixed": "06c1de44d378ec5439db17bf476507d68589bfe9"
                },
                {
                  "fixed": "450b6b22acdaac67a18eaf5ed498421ffcf10051"
                },
                {
                  "fixed": "ca7d00c5656d1791e28369919e3e10febe9c3b16"
                },
                {
                  "fixed": "8aa79dfb216b865e96ff890bc4ea71650f9bc8d7"
                },
                {
                  "fixed": "8a90d3fc7c24608548d3a750671f9dac21d1a462"
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                {
                  "fixed": "388f1c954019f253a8383f7eb733f38d541e10b6"
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                {
                  "fixed": "919f18f961c03d6694aa726c514184f2311a4614"
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "2.6.22"
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            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "4.20.0"
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                  "fixed": "5.4.282"
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
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                {
                  "fixed": "5.10.224"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.165"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.105"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.46"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
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                {
                  "fixed": "6.10.5"
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              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-44948.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.410633943Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-265688.html",
        "https://git.kernel.org/stable/c/06c1de44d378ec5439db17bf476507d68589bfe9",
        "https://git.kernel.org/stable/c/34f36e6ee5bd7eff8b2adcd9fcaef369f752d82e",
        "https://git.kernel.org/stable/c/388f1c954019f253a8383f7eb733f38d541e10b6",
        "https://git.kernel.org/stable/c/450b6b22acdaac67a18eaf5ed498421ffcf10051",
        "https://git.kernel.org/stable/c/8a90d3fc7c24608548d3a750671f9dac21d1a462",
        "https://git.kernel.org/stable/c/8aa79dfb216b865e96ff890bc4ea71650f9bc8d7",
        "https://git.kernel.org/stable/c/919f18f961c03d6694aa726c514184f2311a4614",
        "https://git.kernel.org/stable/c/ca7d00c5656d1791e28369919e3e10febe9c3b16",
        "https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html",
        "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/44xxx/CVE-2024-44948.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-44948",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/44xxx/CVE-2024-44948.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-44948",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 488419,
  "published_at": "2024-09-04T18:35:48.98+00:00"
}