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Linux KernelOperating system · Linux

CVE-2026-53342

MEDIUM · 5.5 CVSS v3.1 Published 2026-07-01
Fix available
A fix is available. Upgrade to 6.18.36 / 7.0.13 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available 7 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: arm64: mm: call pagetable dtor when freeing hot-removed page tables Since 5e8eb9aeeda3 ("arm64: mm: always call PTE/PMD ctor in __create_pgd_mapping()") page-table allocation on ARM64 always calls pagetable_{pte,pmd,pud,p4d}_ctor(). This sets the page_type to PGTY_table, increments NR_PAGETABLE and possible allocates a PTL. However the matching pagetable_dtor() calls were never added. With DEBUG_VM enabled on kernel versions prior to v6.17 without 2dfcd1608f3a9 ("mm/page_alloc: let page freeing clear any set page type") this leads to the following warning when freeing these pages due to page->page_type sharing page->_mapcount: BUG: Bad page state in process ... pfn:284fbb page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x284fbb flags: 0x17fffc000000000(node=0|zone=2|lastcpupid=0x1ffff) page_type: f2(table) page dumped because: nonzero mapcount Call trace: bad_page+0x13c/0x160 __free_frozen_pages+0x6cc/0x860 ___free_pages+0xf4/0x180 free_pages+0x54/0x80 free_hotplug_page_range.part.0+0x58/0x90 free_empty_tables+0x438/0x500 __remove_pgd_mapping.constprop.0+0x60/0xa8 arch_remove_memory+0x48/0x80 try_remove_memory+0x158/0x1d8 offline_and_remove_memory+0x138/0x180 It can also lead to leaking the ptl allocation if ALLOC_SPLIT_PTLOCKS is defined and incorrect NR_PAGETABLE stats. Fix this by calling pagetable_dtor() in free_hotplug_pgtable_page() prior to freeing the page to undo the effects of calling pagetable_*_ctor().

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In ARM64 Linux kernel, page-table allocation always calls pagetable_ctor() which sets page_type to PGTY_table, increments NR_PAGETABLE, and allocates a PTL. However, the matching pagetable_dtor() was never added in the free path. When hot-removing memory, this causes a 'Bad page state' BUG with DEBUG_VM, leaks PTL allocations, and corrupts NR_PAGETABLE stats. The fix is to call pagetable_dtor() in free_hotplug_pgtable_page() before freeing.

MitigationApply the kernel patch that adds pagetable_dtor() call in free_hotplug_pgtable_page() prior to freeing the page. This is a code-level fix requiring kernel rebuild.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.16, < 6.18.36>= 6.19, < 7.0.13= 7.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check kernel version
    Run `uname -r` or view /proc/version to get the running kernel version
    Affected if Version is >= 6.16 and < 6.18.36, OR >= 6.19 and < 7.0.13, OR equals 7.1
  2. Verify ARM64 architecture
    Run `uname -m` or check /proc/cpuinfo for aarch64 or arm64
    Affected if Running on ARM64/aarch64 architecture and kernel version is in the affected range
  3. Check if DEBUG_VM is enabled
    Check kernel config for CONFIG_DEBUG_VM=y (found in /boot/config-$(uname -r), /proc/config.gz, or /lib/modules/$(uname -r)/build/.config)
    Affected if DEBUG_VM is enabled and the kernel version/arch are affected - page state corruption warnings will appear in dmesg
  4. Inspect NR_PAGETABLE statistics
    Check /proc/meminfo for NR_PAGETABLE entry and compare against expected value for your system workload; also monitor for unexpected growth over time
    Affected if NR_PAGETABLE value is abnormally high or steadily increasing without corresponding memory pressure

You are affected if running an ARM64 kernel version 6.16 to < 6.18.36, 6.19 to < 7.0.13, or 7.1 with hot-removed page tables and observing incorrect NR_PAGETABLE counts or DEBUG_VM warnings.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.18.36 / 7.0.13 or later
Fixed in 6.18.367.0.13
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch that adds pagetable_dtor() call in free_hotplug_pgtable_page() prior to freeing the page. This is a code-level fix requiring kernel rebuild.

Recommended fix High confidence

Upgrade to 6.18.36+ (for 6.16-6.18.x), 7.0.13+ (for 6.19-7.0.x), or 7.2+ (for 7.1)

  1. Identify your current kernel version using 'uname -r' or 'cat /proc/version'
  2. Determine which version range you fall into: 6.16-6.18.x, 6.19-7.0.x, or 7.1
  3. For 6.16-6.18.x: upgrade to kernel version 6.18.36 or later
  4. For 6.19-7.0.x: upgrade to kernel version 7.0.13 or later
  5. For 7.1: upgrade to kernel version 7.2 or later
  6. Reboot into the new kernel and verify the fix is applied by checking the kernel release notes or changelog for CVE-2026-53342
Caveat Kernel upgrades are generally safe but may require reboot; test in staging if possible

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53342 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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