CVE-2026-43303

A flaw was found in the Linux kernel's memory management subsystem. When pages are freed, the page->private field is not properly cleared. If these pages are later reallocated as high-order pages and split, the tail pages can retain stale page->private values. This can lead to a use-after-free vulnerability in the swap subsystem, where incorrect assumptions about the page->private value can cause the system to crash.

A stale page private value can remain on freed pages and later survive allocation as a high-order page followed by split_page. The swap subsystem assumes newly allocated pages have page private set to zero and may treat the stale value as a valid swap count continuation, leading to traversal of poisoned or invalid list state and a UAF style wild memory access in the swapoff path. For the CVSS the PR:L is used for the paranoid case because a local user may be able to influence allocator state and page reuse even though the direct crash trace involves swapoff. The issue is not network reachable. Impact is at least local denial of service via kernel crash, and in worst case may allow confidentiality or integrity impact due to core memory management corruption.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.