CVE-2026-68271 drm/nouveau: fix reversed error cleanup order in ucopy functions
A local attacker can trigger a kernel oops via a null pointer dereference in the nouveau driver's ucopy functions, 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-2026-68271?
CVE-2026-68271 is a vulnerability in Linux, published on 10 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:
drm/nouveau: fix reversed error cleanup order in ucopy functions
nouveau_uvmm_vm_bind_ucopy() and nouveau_exec_ucopy() place their error cleanup labels in allocation order rather than reverse allocation order. On a u_memcpya() failure for in_sync.s, the goto to err_free_ops (or err_free_pushs) frees the first allocation and then falls through to err_free_ins, which calls u_free() on args->in_sync.s.
Since args->in_sync.s still holds the ERR_PTR returned by the failed u_memcpya(), and ERR_PTR values are not caught by ZERO_OR_NULL_PTR(), kvfree() proceeds to dereference it, which can result in a kernel oops. A failure for out_sync.s instead jumps to err_free_ins and skips freeing the first allocation, leading to a memory leak.
Fix by swapping the cleanup label order so resources are freed in the correct reverse allocation sequence.
Which versions are affected by CVE-2026-68271?
How do I fix CVE-2026-68271?
Apply the vendor's patch.
Is CVE-2026-68271 being exploited?
There is no known exploitation of CVE-2026-68271 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68271, DEBIAN-CVE-2026-68271, GHSA-hvp2-xg6j-p7j9, UBUNTU-CVE-2026-68271.