CVE-2026-74520

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

iommu/iommufd: Fix IOPF group ownership UAF

iopf_group_alloc() links each last-page IOPF group into the generic IOPF

pending list before invoking the domain fault handler.

iommufd_fault_iopf_handler() also queued an accepted group in the

IOMMUFD deliver list without removing it from the generic pending list.

When detach or HWPT replacement drops the device's IOPF reference count

to zero, an IOMMU driver may call iopf_queue_remove_device(). That

function responds to and frees groups through the generic pending list

without removing the same groups from IOMMUFD's deliver list or response

xarray. A later read, response, or cleanup can then access the freed

group and cause a UAF.

Fix this by dequeuing an accepted group from the generic pending list

before IOMMUFD queues it for userspace response.

Make iopf_group_response() send a response regardless of pending-list

membership, so the dequeued group can still be completed by IOMMUFD.