The Linux kernel memory manager for 32‑bit x86 systems incorrectly assumes that the functions to test for special pages, pmd_special() and pud_special(), are implemented when Transparent Huge Pages (THP) are enabled. When a huge zero page is reclaimed, the missing check triggers a warning followed by ‘Bad rss‑counter state’ and ‘Bad page state’ bugs. These failures can lead to corruption of page state information, memory accounting errors, and potentially a system crash. The flaw is identified as CWE‑166, inappropriate handling of special page attributes, and manifests as incorrect page state tracking.

All Linux kernel builds running on 32‑bit x86 architectures with Transparent Huge Pages enabled before the regression fix are affected. No specific kernel releases are listed, so any kernel version operating with THP on a 32‑bit x86 platform prior to the patch is vulnerable. The vulnerability applies broadly to all such kernels regardless of version or configuration other than THP being active.

The CVSS score of 7.8 classifies this as high severity. The EPSS score of <1% indicates a very low probability that the flaw has been actively exploited. It is not listed in the CISA KEV catalog. The vulnerability is most likely exploitable by local or privileged users who can trigger conditions that lead to a huge zero page reclamation, such as allocating large memory regions or forcing memory pressure. Based on the description, it is inferred that an attacker would need local access and would trigger the bug by exercising memory‑intensive operations that involve THP.