Vulnerability-Lookup

GHSA-MR2C-GWQW-3X39

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-23 15:33

Details

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

mm/page_table_check: skip special zero mappings

page_table_check_set() and page_table_check_clear() account mappings based on PageAnon(). Shared zero-page PTEs and huge zero PMDs are special mappings, but page_table_check can still account them as file-backed pages.

An unprivileged process can populate enough zero mappings to overflow file_map_count and hit the existing BUG_ON(). The PTE path can do this with the shared zero page, and the PMD path can do the same with huge zero mappings.

Skip special zero mappings in the user page-table accounting paths. Keep the PTE-side pte_special() check, and identify huge zero PMDs from the mapped folio instead of pmd_special(). That covers architectures where pmd_special() is a no-op without adding huge_zero_pfn checks to the generic counter helpers.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-74600"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:32Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_table_check: skip special zero mappings\n\npage_table_check_set() and page_table_check_clear() account mappings based\non PageAnon().  Shared zero-page PTEs and huge zero PMDs are special\nmappings, but page_table_check can still account them as file-backed\npages.\n\nAn unprivileged process can populate enough zero mappings to overflow\nfile_map_count and hit the existing BUG_ON().  The PTE path can do this\nwith the shared zero page, and the PMD path can do the same with huge zero\nmappings.\n\nSkip special zero mappings in the user page-table accounting paths.  Keep\nthe PTE-side pte_special() check, and identify huge zero PMDs from the\nmapped folio instead of pmd_special().  That covers architectures where\npmd_special() is a no-op without adding huge_zero_pfn checks to the\ngeneric counter helpers.",
  "id": "GHSA-mr2c-gwqw-3x39",
  "modified": "2026-08-23T15:33:03Z",
  "published": "2026-08-22T18:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74600"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7755be923e325dc300f4b0c3e1ad7e91b28b3cb9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8db4bab826ccc9ec10fa41736a48031cd338d392"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-74600 (GCVE-0-2026-74600)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:31 – Updated: 2026-08-23 12:47

Title

mm/page_table_check: skip special zero mappings

Summary

In the Linux kernel, the following vulnerability has been resolved: mm/page_table_check: skip special zero mappings page_table_check_set() and page_table_check_clear() account mappings based on PageAnon(). Shared zero-page PTEs and huge zero PMDs are special mappings, but page_table_check can still account them as file-backed pages. An unprivileged process can populate enough zero mappings to overflow file_map_count and hit the existing BUG_ON(). The PTE path can do this with the shared zero page, and the PMD path can do the same with huge zero mappings. Skip special zero mappings in the user page-table accounting paths. Keep the PTE-side pte_special() check, and identify huge zero PMDs from the mapped folio instead of pmd_special(). That covers architectures where pmd_special() is a no-op without adding huge_zero_pfn checks to the generic counter helpers.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/7755be923e325dc30…
https://git.kernel.org/stable/c/b726eb3c94d23e09d…
https://git.kernel.org/stable/c/8db4bab826ccc9ec1…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: df4e817b710809425d899340dbfa8504a3ca4ba5 , < 7755be923e325dc300f4b0c3e1ad7e91b28b3cb9 (git) Affected: df4e817b710809425d899340dbfa8504a3ca4ba5 , < b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc (git) Affected: df4e817b710809425d899340dbfa8504a3ca4ba5 , < 8db4bab826ccc9ec10fa41736a48031cd338d392 (git)
Linux	Linux	Affected: 5.17 Unaffected: 0 , < 5.17 (semver) Unaffected: 6.18.46 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/page_table_check.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "7755be923e325dc300f4b0c3e1ad7e91b28b3cb9",
              "status": "affected",
              "version": "df4e817b710809425d899340dbfa8504a3ca4ba5",
              "versionType": "git"
            },
            {
              "lessThan": "b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc",
              "status": "affected",
              "version": "df4e817b710809425d899340dbfa8504a3ca4ba5",
              "versionType": "git"
            },
            {
              "lessThan": "8db4bab826ccc9ec10fa41736a48031cd338d392",
              "status": "affected",
              "version": "df4e817b710809425d899340dbfa8504a3ca4ba5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/page_table_check.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "lessThan": "5.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                },
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                }
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_table_check: skip special zero mappings\n\npage_table_check_set() and page_table_check_clear() account mappings based\non PageAnon().  Shared zero-page PTEs and huge zero PMDs are special\nmappings, but page_table_check can still account them as file-backed\npages.\n\nAn unprivileged process can populate enough zero mappings to overflow\nfile_map_count and hit the existing BUG_ON().  The PTE path can do this\nwith the shared zero page, and the PMD path can do the same with huge zero\nmappings.\n\nSkip special zero mappings in the user page-table accounting paths.  Keep\nthe PTE-side pte_special() check, and identify huge zero PMDs from the\nmapped folio instead of pmd_special().  That covers architectures where\npmd_special() is a no-op without adding huge_zero_pfn checks to the\ngeneric counter helpers."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-23T12:47:40.893Z",
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          "url": "https://git.kernel.org/stable/c/b726eb3c94d23e09da0e0f46b0fa09fb2b5d99cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/8db4bab826ccc9ec10fa41736a48031cd338d392"
        }
      ],
      "title": "mm/page_table_check: skip special zero mappings",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74600",
    "datePublished": "2026-08-22T15:31:49.334Z",
    "dateReserved": "2026-08-15T05:44:03.919Z",
    "dateUpdated": "2026-08-23T12:47:40.893Z",
    "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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-MR2C-GWQW-3X39

CVE-2026-74600 (GCVE-0-2026-74600)

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Sightings

Nomenclature