CVE-2026-43303

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

mm/page_alloc: clear page->private in free_pages_prepare()

Several subsystems (slub, shmem, ttm, etc.) use page->private but don't

clear it before freeing pages. When these pages are later allocated as

high-order pages and split via split_page(), tail pages retain stale

page->private values.

This causes a use-after-free in the swap subsystem. The swap code uses

page->private to track swap count continuations, assuming freshly

allocated pages have page->private == 0. When stale values are present,

swap_count_continued() incorrectly assumes the continuation list is valid

and iterates over uninitialized page->lru containing LIST_POISON values,

causing a crash:

KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107]

RIP: 0010:__do_sys_swapoff+0x1151/0x1860

Fix this by clearing page->private in free_pages_prepare(), ensuring all

freed pages have clean state regardless of previous use.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References