Use-After-Free Vulnerability in Linux Kernel ACPI Functionality

CVE-2026-93251

What is CVE-2026-93251?

A vulnerability in the Linux kernel's ACPI functionality can lead to a use-after-free condition. This occurs when the function acpi_get_first_physical_node() may return a stale device pointer due to race conditions. The function, typically called to obtain the first 'physical' device linked to a given ACPI companion, risks returning a pointer to a device that has already been freed. If a caller then attempts to access this device, it may lead to unpredictable behavior or system crashes. To mitigate this, a new function has been introduced that accurately retrieves the first physical device while ensuring proper reference counting before returning the device pointer.

References