CVE-2026-80894 iommufd: Fix wrong hwpt passed to iommufd_auto_response_faults on replace

What is CVE-2026-80894?

CVE-2026-80894 is a vulnerability in Linux, published on 4 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:

iommufd: Fix wrong hwpt passed to iommufd_auto_response_faults on replace

iommufd_hwpt_replace_device() calls:

iommufd_auto_response_faults(hwpt, old_handle);

passing the *new* hwpt together with the handle of the device's *old* domain. This should be a parameter mismatch:

1. Semantically, iommufd_auto_response_faults(x, handle) scans x->fault's deliver list and response xarray for groups matching "handle". A group is queued under the hwpt that was attached at fault-delivery time. old_handle is fetched *before* the domain switch, so its group lives on old->fault, not on the new hwpt->fault.

2. Historically, the first argument was "old". The routine was introduced by commit b7d8833677ba ("iommufd: Fault-capable hwpt attach/detach/replace") as __fault_domain_replace_dev() in fault.c, correctly calling iommufd_auto_response_faults(old, curr). Commit fb21b1568ada ("iommufd: Make attach_handle generic than fault specific") moved this into iommufd_hwpt_replace_device() in device.c and swapped it to "hwpt". This should be a refactor regression, not an intentional change.

Fix this by passing "old" instead.

Which versions are affected by CVE-2026-80894?

How do I fix CVE-2026-80894?

Apply the vendor's patch.

Is CVE-2026-80894 being exploited?

There is no known exploitation of CVE-2026-80894 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-80894, DEBIAN-CVE-2026-80894, GHSA-jg86-gjjj-22qv, UBUNTU-CVE-2026-80894.