CVE-2026-52951 drm/xe/dma-buf: handle empty bo and UAF races
A race condition in the Linux kernel's Xe driver allows a use-after-free or null dereference, potentially causing a system crash.
- 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-2026-52951?
CVE-2026-52951 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jun 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:
drm/xe/dma-buf: handle empty bo and UAF races
There look to be some nasty races here when triggering the invalidate_mappings hook:
1) We do xe_bo_alloc() followed by the attach, before the actual full bo init step in xe_dma_buf_init_obj(). However the bo is visible on the attachments list after the attach. This is bad since exporter driver, say amdgpu, can at any time call back into our invalidate_mappings hook, with an empty/bogus bo, leading to potential bugs/crashes.
2) Similar to 1) but here we get a UAF, when the invalidate_mappings hook is triggered. For example, we get as far as xe_bo_init_locked() but this fails in some way. But here the bo will be freed on error, but we still have it attached from dma-buf pov, so if the invalidate_mappings is now triggered then the bo we access is gone and we trigger UAF and more bugs/crashes.
To fix this, move the attach step until after we actually have a fully set up buffer object. Note that the bo is not published to userspace until later, so not sure what the comment "Don't publish the bo until we have a valid attachment", is referring to.
We have at least two different customers reporting hitting a NULL ptr deref in evict_flags when importing something from amdgpu, followed by triggering the evict flow. Hit rate is also pretty low, which would hint at some kind of race, so something like 1) or 2) might explain this.
v2: - Shuffle the order of the ops slightly (no functional change) - Improve the comment to better explain the ordering (Matt B)
(cherry picked from commit af1f2ad0c59fe4e2f924c526f66e968289d77971)
Which versions are affected by CVE-2026-52951?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-52951?
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-2026-52951 being exploited?
There is no known exploitation of CVE-2026-52951 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-52951, DEBIAN-CVE-2026-52951, GHSA-pq4c-fm9x-v9hj, ROOT-OS-UBUNTU-2404-CVE-2026-52951, UBUNTU-CVE-2026-52951.