CVE-2026-68445
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
In the Linux kernel's drm/vc4 driver, vc4_gem_object_mmap() rejects writable mappings of validated shader BOs but leaves VM_MAYWRITE set. Userspace can map the BO read-only and then make it writable with mprotect().
Risk Assessment
This allows userspace to bypass the shader validator and modify code after validation, potentially leading to GPU memory integrity violations and privilege escalation.
Recommendation
Apply the kernel patch that clears VM_MAYWRITE on the read-only path to prevent upgrading the mapping to writable.
Original NVD description (English source)
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.