CVE-2026-93251

Summary

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

ACPI: bus: Introduce acpi_bus_get_primary_device()

The function used for obtaining the first "physical" device for which the given ACPI one is the ACPI companion, acpi_get_first_physical_node(), may return a stale device pointer (mostly in theory) because acpi_unbind_one() may run as a whole after dropping the ACPI device's physical_node_lock in acpi_get_first_physical_node() and before it returns. The last reference to the "physical" device may be dropped then before the pointer to it is returned to the caller.

If that happens and the acpi_get_first_physical_node() caller invokes get_device() on the pointer obtained from it, which is done by the majority of its callers, a use-after-free will occur.

To prepare for addressing this problem, introduce a new function for getting the first "physical" device associated with the given ACPI one (the "primary physical device") that will also reference count the device in question before returning a pointer to it.

Make that new function and acpi_get_first_physical_node() share the physical node list lookup code.

No intentional functional impact.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5657859851abb65105220a6cdb5804926249f714affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 72530e1f72b0515a73fd88292254d04fecf03649affected
LinuxLinux0 < 7.2.6affected
LinuxLinux7.2.6 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References