CVE-2026-74312 vhost/vdpa: validate virtqueue index in mmap and fault paths
An attacker can trigger an out-of-bounds access in the Linux kernel vhost/vdpa module via mmap or fault paths, potentially causing a crash or 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-2026-74312?
CVE-2026-74312 is a high-severity memory corruption vulnerability in Linux, published on 15 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:
vhost/vdpa: validate virtqueue index in mmap and fault paths
vhost_vdpa_mmap() and vhost_vdpa_fault() use vma->vm_pgoff as a virtqueue index for get_vq_notification(), but they do not validate that the index is smaller than v->nvqs.
The ioctl path already performs both a bounds check and array_index_nospec(), but the mmap/fault path only checks that the index fits in u16. This allows an out-of-range queue index to reach driver-specific get_vq_notification() callbacks.
Fix this by extracting a unified vhost_vdpa_get_vq_notification() helper that validates the queue index against v->nvqs and applies array_index_nospec() before calling the driver callback. Both the mmap and fault paths use this helper, and the bounds checking is consolidated into a single location.
From source inspection, the most defensible impact is out-of-bounds access in the callback path, potentially leading to invalid PFN remaps and crash/DoS.
Which versions are affected by CVE-2026-74312?
How do I fix CVE-2026-74312?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-74312 being exploited?
There is no known exploitation of CVE-2026-74312 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74312, DEBIAN-CVE-2026-74312, GHSA-vx5g-7fcv-7h84, UBUNTU-CVE-2026-74312.