A use‑after‑free flaw exists in the Linux kernel’s huge memory handling: the file or shared‑memory RSS counter is updated after the PMD mapping’s folio reference is released. If this folio is the last reference, the counter may read freed memory, allowing an attacker to observe or influence corrupted state. This can result in memory corruption, denial of service, or privilege escalation if escalated appropriately. The vulnerability is a classic Use‑After‑Free defect (CWE‑415).

The issue affects the Linux kernel across all builds that include the original mm/huge_memory code path. No specific version range is listed in the available data, so any kernel revision where the bug resides is potentially vulnerable until patched. If your system uses a recent kernel, consult the vendor’s changelog to confirm whether the fix is present.

The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog. Nonetheless, because it is a kernel‑memory use‑after‑free, the potential impact is high, and the attack is presumed to require local or privileged access to allocate and manipulate huge pages. The lack of a CVSS score limits quantification, but the nature of the flaw suggests a serious risk if exploited. Periodic monitoring for kernel crashes or segfaults is advisable while a patch is pending.