CVE-2026-64227

In the Linux kernel, the following vulnerability has been resolved:

ACPI: driver: Check ACPI_COMPANION() against NULL during probe

Since every platform driver can be forced to match a device that doesn't match its list of device IDs because of device_match_driver_override(), platform drivers that rely on the existence of a device's ACPI companion object should verify its presence.

Accordingly, add requisite ACPI_COMPANION() or ACPI_HANDLE() checks against NULL to 13 platform drivers handling core ACPI devices.

Also change the value returned by the ACPI thermal zone driver when the device's ACPI companion is not present to -ENODEV for consistency with the other drivers.

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.