CVE-2026-89451 iommu/sva: Set handle->dev before the SVA handle is visible
A race condition in the Linux kernel IOMMU SVA subsystem allows a local attacker to trigger a null pointer dereference, 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-2026-89451?
CVE-2026-89451 is a vulnerability in Linux, published on 11 Sep 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:
iommu/sva: Set handle->dev before the SVA handle is visible
iommu_attach_device_pasid() installs the new SVA attach handle in the group PASID lookup before iommu_sva_bind_device() returns. A concurrent bind can therefore find and reuse the same handle after iommu_sva_lock is dropped.
handle->dev was initialized after dropping iommu_sva_lock. This leaves a window where a racing bind can return a handle whose dev pointer is still NULL. A subsequent iommu_sva_unbind_device() can then dereference it via handle->dev->iommu_group.
Initialize handle->dev before releasing iommu_sva_lock so any visible SVA handle is fully initialized.
Which versions are affected by CVE-2026-89451?
How do I fix CVE-2026-89451?
Apply the vendor's patch.
Is CVE-2026-89451 being exploited?
There is no known exploitation of CVE-2026-89451 in the wild and no public exploit code.
Sources
Also known as AZL-100277, BELL-CVE-2026-89451, DEBIAN-CVE-2026-89451, GHSA-mm8r-pp22-xwxg, UBUNTU-CVE-2026-89451.