Linux Kernel Memory Management Vulnerability in Folio Migration

CVE-2026-89755

What is CVE-2026-89755?

A vulnerability in the Linux kernel's memory management process allows for the potential misuse of stale mappings during folio migrations. When the function __migrate_device_pages() executes, it retrieves mapping information before a folio is freed from swapcache. If successful, the mapping becomes outdated, which can lead the folio_migrate_mapping() to reference invalid information. This flaw might trigger reference accounting inconsistencies and could disrupt folio integrity. To mitigate this, the kernel's logic for resetting the mapping state must be updated immediately after swapcache operations, ensuring accurate migration handling for split folios.

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