CVE-2026-68445 drm/vc4: Prevent shader BO mappings from becoming writable
Attackers can bypass GPU shader validation by making read-only mappings writable, potentially executing malicious code or escalating privileges.
- 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-2026-68445?
CVE-2026-68445 is a high-severity vulnerability in Linux, published on 12 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/vc4: Prevent shader BO mappings from becoming writable
vc4_gem_object_mmap() rejects a writable mapping of a validated shader BO, but leaves VM_MAYWRITE set. Userspace can map the BO read-only and then turn it writable with mprotect().
Validated shader BOs must stay read-only: the validator checks the instructions once and the GPU trusts them afterwards. A writable mapping lets userspace rewrite the code after validation, bypassing the validator.
Clear VM_MAYWRITE on the read-only path so the mapping cannot be upgraded, as i915 already does for its read-only objects.
Which versions are affected by CVE-2026-68445?
How do I fix CVE-2026-68445?
Apply the vendor's patch.
Is CVE-2026-68445 being exploited?
There is no known exploitation of CVE-2026-68445 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68445, DEBIAN-CVE-2026-68445, GHSA-rw5p-xff5-86qj, UBUNTU-CVE-2026-68445.