CVE-2026-80687 iommufd/viommu: Release the igroup lock on the vdevice_size error path
A missing lock release in the Linux kernel iommufd driver allows local attackers to cause a deadlock and 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-2026-80687?
CVE-2026-80687 is a denial of service vulnerability in Linux, published on 28 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:
iommufd/viommu: Release the igroup lock on the vdevice_size error path
iommufd_vdevice_alloc_ioctl() takes idev->igroup->lock, then validates the driver's vdevice_size against the core structure size with a WARN_ON_ONCE. On failure that guard jumps to out_put_idev, below out_unlock_igroup, so it skips the mutex_unlock(), leaving the igroup lock held and deadlocking the next vDEVICE operation on that group.
Jump to out_unlock_igroup instead.
Which versions are affected by CVE-2026-80687?
How do I fix CVE-2026-80687?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-80687 being exploited?
There is no known exploitation of CVE-2026-80687 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-80687, DEBIAN-CVE-2026-80687, GHSA-fh38-x9qp-g22j, UBUNTU-CVE-2026-80687.