CVE-2026-74716 accel/amdxdna: Fix locally exploitable BUG_ON in amdxdna_insert_pages()
A local attacker can trigger a kernel BUG_ON crash in the AMD XDNA driver by manipulating memory mappings, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74716?
CVE-2026-74716 is a denial of service vulnerability in Linux, published on 22 Aug 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:
accel/amdxdna: Fix locally exploitable BUG_ON in amdxdna_insert_pages()
In amdxdna_insert_pages(), vm_flags_mod() sets VM_MIXEDMAP and clears VM_PFNMAP. If an unprivileged userspace process mmaps a non-imported GEM object and then calls madvise(MADV_DONTNEED), the PTEs will be successfully cleared because VM_MIXEDMAP allows this (unlike VM_PFNMAP).
When userspace subsequently accesses the memory, drm_gem_shmem_fault() handles the page fault and attempts to map the backing shmem page via vmf_insert_pfn() which calls vmf_insert_pfn_prot(). Because the backing shmem page is normal system memory (pfn_valid(pfn) is true) and the VMA now has VM_MIXEDMAP set, won't this predictably trigger the explicit assertion BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn))
Fix by removing the vm_flags_mod() call and replacing the vm_insert_pages() pre-population with the handle_mm_fault() loop that was already used for the import (dma-buf) path.
Which versions are affected by CVE-2026-74716?
How do I fix CVE-2026-74716?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-74716 being exploited?
There is no known exploitation of CVE-2026-74716 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74716, DEBIAN-CVE-2026-74716, GHSA-44jx-474f-m2qv, UBUNTU-CVE-2026-74716.