Vulnerability-Lookup

GHSA-RMR6-R8PG-M34Q

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

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

x86/mm: Fix freeing of PMD-sized vmemmap pages

Commit bf9e4e30f353 ("x86/mm: use pagetable_free()"), switched from freeing non-boot page tables through __free_pages() to pagetable_free().

However, the function is also called to free vmemmap pages.

Given that vmemmap pages are not page tables, already the page_ptdesc(page) is wrong. But worse, pagetable_free() calls:

__free_pages(page, compound_order(page));

Since vmemmap pages are not compound pages (see vmemmap_alloc_block()) -- except for HVO, which doesn't apply here -- only first page of a PMD-sized vmemmap page is freed, leaking the other ones.

Fix it by properly decoupling pagetable and vmemmap freeing. free_pagetable() no longer has to mess with SECTION_INFO, as only the vmemmap is marked like that in register_page_bootmem_memmap().

The indentation in remove_pmd_table() is messed up. Fix that while touching it.

Bootmem info handling will soon be fixed up. For now, handle it similar to free_pagetable(), just avoiding the ifdef.

[ dhansen: changelog munging. More imperative voice ]

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64302"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:11Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm: Fix freeing of PMD-sized vmemmap pages\n\nCommit bf9e4e30f353 (\"x86/mm: use pagetable_free()\"), switched from\nfreeing non-boot page tables through __free_pages() to\npagetable_free().\n\nHowever, the function is also called to free vmemmap pages.\n\nGiven that vmemmap pages are not page tables, already the page_ptdesc(page)\nis wrong. But worse, pagetable_free() calls:\n\n\t__free_pages(page, compound_order(page));\n\nSince vmemmap pages are not compound pages (see vmemmap_alloc_block())\n-- except for HVO, which doesn\u0027t apply here -- only first page of a\nPMD-sized vmemmap page is freed, leaking the other ones.\n\nFix it by properly decoupling pagetable and vmemmap freeing.\nfree_pagetable() no longer has to mess with SECTION_INFO, as only the\nvmemmap is marked like that in register_page_bootmem_memmap().\n\nThe indentation in remove_pmd_table() is messed up. Fix that while\ntouching it.\n\nBootmem info handling will soon be fixed up. For now, handle it\nsimilar to free_pagetable(), just avoiding the ifdef.\n\n[ dhansen: changelog munging. More imperative voice ]",
  "id": "GHSA-rmr6-r8pg-m34q",
  "modified": "2026-07-25T12:31:30Z",
  "published": "2026-07-25T12:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64302"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/03f6ecbc446c33b38fd452cd3c494092a8116967"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/39406c05f8f150f1685839acd38ffdd69ff92031"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/add1e4112e00b619614784bf630aeebfdefa23e1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64302 (GCVE-0-2026-64302)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-07-25 08:49

Title

x86/mm: Fix freeing of PMD-sized vmemmap pages

Summary

In the Linux kernel, the following vulnerability has been resolved: x86/mm: Fix freeing of PMD-sized vmemmap pages Commit bf9e4e30f353 ("x86/mm: use pagetable_free()"), switched from freeing non-boot page tables through __free_pages() to pagetable_free(). However, the function is also called to free vmemmap pages. Given that vmemmap pages are not page tables, already the page_ptdesc(page) is wrong. But worse, pagetable_free() calls: __free_pages(page, compound_order(page)); Since vmemmap pages are not compound pages (see vmemmap_alloc_block()) -- except for HVO, which doesn't apply here -- only first page of a PMD-sized vmemmap page is freed, leaking the other ones. Fix it by properly decoupling pagetable and vmemmap freeing. free_pagetable() no longer has to mess with SECTION_INFO, as only the vmemmap is marked like that in register_page_bootmem_memmap(). The indentation in remove_pmd_table() is messed up. Fix that while touching it. Bootmem info handling will soon be fixed up. For now, handle it similar to free_pagetable(), just avoiding the ifdef. [ dhansen: changelog munging. More imperative voice ]

Severity

No CVSS data available.

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/add1e4112e00b6196…
https://git.kernel.org/stable/c/03f6ecbc446c33b38…
https://git.kernel.org/stable/c/39406c05f8f150f16…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: a1593c90896babf33e947910c7aecb9f50bab993 , < add1e4112e00b619614784bf630aeebfdefa23e1 (git) Affected: bf9e4e30f3538391745a99bc2268ec4f5e4a401e , < 03f6ecbc446c33b38fd452cd3c494092a8116967 (git) Affected: bf9e4e30f3538391745a99bc2268ec4f5e4a401e , < 39406c05f8f150f1685839acd38ffdd69ff92031 (git) Affected: 6.18.7 , < 6.18.39 (semver)
Linux	Linux	Affected: 6.19 Unaffected: 0 , < 6.19 (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/mm/init_64.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "add1e4112e00b619614784bf630aeebfdefa23e1",
              "status": "affected",
              "version": "a1593c90896babf33e947910c7aecb9f50bab993",
              "versionType": "git"
            },
            {
              "lessThan": "03f6ecbc446c33b38fd452cd3c494092a8116967",
              "status": "affected",
              "version": "bf9e4e30f3538391745a99bc2268ec4f5e4a401e",
              "versionType": "git"
            },
            {
              "lessThan": "39406c05f8f150f1685839acd38ffdd69ff92031",
              "status": "affected",
              "version": "bf9e4e30f3538391745a99bc2268ec4f5e4a401e",
              "versionType": "git"
            },
            {
              "lessThan": "6.18.39",
              "status": "affected",
              "version": "6.18.7",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/mm/init_64.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "6.18.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc1",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm: Fix freeing of PMD-sized vmemmap pages\n\nCommit bf9e4e30f353 (\"x86/mm: use pagetable_free()\"), switched from\nfreeing non-boot page tables through __free_pages() to\npagetable_free().\n\nHowever, the function is also called to free vmemmap pages.\n\nGiven that vmemmap pages are not page tables, already the page_ptdesc(page)\nis wrong. But worse, pagetable_free() calls:\n\n\t__free_pages(page, compound_order(page));\n\nSince vmemmap pages are not compound pages (see vmemmap_alloc_block())\n-- except for HVO, which doesn\u0027t apply here -- only first page of a\nPMD-sized vmemmap page is freed, leaking the other ones.\n\nFix it by properly decoupling pagetable and vmemmap freeing.\nfree_pagetable() no longer has to mess with SECTION_INFO, as only the\nvmemmap is marked like that in register_page_bootmem_memmap().\n\nThe indentation in remove_pmd_table() is messed up. Fix that while\ntouching it.\n\nBootmem info handling will soon be fixed up. For now, handle it\nsimilar to free_pagetable(), just avoiding the ifdef.\n\n[ dhansen: changelog munging. More imperative voice ]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-25T08:49:37.621Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/add1e4112e00b619614784bf630aeebfdefa23e1"
        },
        {
          "url": "https://git.kernel.org/stable/c/03f6ecbc446c33b38fd452cd3c494092a8116967"
        },
        {
          "url": "https://git.kernel.org/stable/c/39406c05f8f150f1685839acd38ffdd69ff92031"
        }
      ],
      "title": "x86/mm: Fix freeing of PMD-sized vmemmap pages",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64302",
    "datePublished": "2026-07-25T08:49:37.621Z",
    "dateReserved": "2026-07-19T15:36:31.779Z",
    "dateUpdated": "2026-07-25T08:49:37.621Z",
    "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.

Action not permitted

GHSA-RMR6-R8PG-M34Q

CVE-2026-64302 (GCVE-0-2026-64302)

Tags

Sightings

Nomenclature