CVE-2026-92521 ACPI: PCI: Clear driver_data on all paths that free the acpi_pci_root
A use-after-free vulnerability in the Linux kernel ACPI PCI subsystem allows local attackers to cause denial of service or potentially execute code via dangling pointers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-92521?
CVE-2026-92521 is an use after free vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ACPI: PCI: Clear driver_data on all paths that free the acpi_pci_root
acpi_pci_root_add() assigns the freshly allocated root to device->driver_data before dmar_device_add() and pci_acpi_scan_root(). Both failure paths reach the end: label where root is kfree()'d, but only the pci_acpi_scan_root() path clears driver_data first.
When dmar_device_add() fails during a hot-add, root is freed while device->driver_data still points at it. The ACPI core does not clear driver_data on attach failure, so a later acpi_pci_find_root() call may dereference this dangling pointer.
acpi_pci_root_remove() has the same problem: it frees root without clearing device->driver_data, leaving a dangling pointer behind after the root bridge is removed.
Move the NULL assignment to the shared end: label so every error path in acpi_pci_root_add() clears driver_data before freeing root, and clear it in acpi_pci_root_remove() as well, so the object is never left reachable through driver_data after being freed.
Which versions are affected by CVE-2026-92521?
How do I fix CVE-2026-92521?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-92521 being exploited?
There is no known exploitation of CVE-2026-92521 in the wild and no public exploit code.
Sources
Also known as AZL-102986, BELL-CVE-2026-92521, DEBIAN-CVE-2026-92521, GHSA-5pq6-vgcp-vv3f, UBUNTU-CVE-2026-92521.