The Linux kernel contains a flaw in the ACPI processor errata handling routine that may cause a use‑after‑free when a device pointer is dereferenced after the kernel has released its reference to the underlying device object. This flaw is a classic null‑pointer dereference that can corrupt kernel memory and, if successfully exploited, could lead to kernel panic or privilege escalation.

All Linux kernel versions that include the ACPI processor errata logic before the mentioned upstream commit are affected. The change applies to kernel releases that contain the acpi_processor_errata_piix4 function, which are all kernels up to the point where the patch was integrated. Operators should verify whether their deployed kernel incorporates this fix.

The CVSS score of 5.5 indicates a moderate severity. The EPSS score of less than 1 % suggests a low current likelihood of exploitation. The vulnerability is not listed in CISA’s KEV catalog. Exploitation would require the attacker to trigger the faulty code path in kernel mode, most likely through local or privilege‑elevated access. No publicly available exploits are currently documented, but successful exploitation could disrupt the affected system or provide a foothold for higher‑privilege attacks.