Description
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 ]
Published: 2026-07-25
Score: n/a
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Thu, 30 Jul 2026 04:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-401

Thu, 30 Jul 2026 00:15:00 +0000


Sat, 25 Jul 2026 09:30:00 +0000

Type Values Removed Values Added
Description 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 ]
Title x86/mm: Fix freeing of PMD-sized vmemmap pages
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-25T08:49:37.621Z

Reserved: 2026-07-19T15:36:31.779Z

Link: CVE-2026-64302

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity :

Publid Date: 2026-07-25T00:00:00Z

Links: CVE-2026-64302 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-07-30T04:15:06Z

Weaknesses
  • CWE-401

    Missing Release of Memory after Effective Lifetime

  • CWE-772

    Missing Release of Resource after Effective Lifetime