CVE-2026-80686

Description

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.

References

• https://git.kernel.org/stable/c/26f9ca8ed42cba25d2c75daff13561cce6019395
• https://git.kernel.org/stable/c/2be94d6b20789b8865b1864dae5fe458ca85e019
• https://git.kernel.org/stable/c/42f30fa5481a1f90571ccdfbb20d2e25e47ae76e
• https://git.kernel.org/stable/c/5b948706f11a950bc73c5304630d0a7eafc40daf
• https://git.kernel.org/stable/c/63867c82d0c0c2d182016a32b1cc0103116b0ea5