Bug 2525467 (CVE-2026-80686)

Summary: CVE-2026-80686 kernel: mm: migrate_device: fix pte_pfn/pte_dirty called on non-present PTE
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's memory management component. Specifically, the `migrate_device` functionality may attempt to access memory page table entries (PTEs) that are not present. This incorrect handling can lead to system instability, potentially causing a system crash (Denial of Service) or inaccurate accounting of modified memory pages.
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Description OSIDB Bzimport 2026-08-28 07:46:28 UTC 
In the Linux kernel, the following vulnerability has been resolved:

mm: migrate_device: fix pte_pfn/pte_dirty called on non-present PTE

pte_pfn() and pte_dirty() have undefined behaviour when called on a
non-present PTE. In migrate_vma_collect_pmd(), these functions may be
invoked on non-present entries (e.g., device-private entries), leading
to potential crashes from pte_pfn() or incorrect dirty folio accounting
from pte_dirty(). Fix both by guarding with pte_present() checks.
Comment 1 gkamathe 2026-09-01 07:04:45 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082802-CVE-2026-80686-a4ef@gregkh/T