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

> A logic error in the Linux kernel iommufd subsystem causes incorrect fault handling during device replacement, potentially leading to denial of service.

- **Severity:** Not scored
- **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:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** BELL-CVE-2026-80894, DEBIAN-CVE-2026-80894, GHSA-jg86-gjjj-22qv, UBUNTU-CVE-2026-80894

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80894 and fix it if it is affected.

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

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-80894/ (Markdown: https://insights.sbomify.com/CVE-2026-80894/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80894
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80894
- OSV: https://osv.dev/vulnerability/CVE-2026-80894

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80894/
Summaries are generated and may contain mistakes; the official description above is the record.