# CVE-2026-90242: iommu/vt-d: Fix iopf_refcount leak on RID domain replacement

> A reference count leak in the Linux kernel IOMMU driver can cause a warning and potential resource exhaustion when replacing device domains.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90242, DEBIAN-CVE-2026-90242, GHSA-f898-qwj6-vcxv, UBUNTU-CVE-2026-90242

## What is CVE-2026-90242?

CVE-2026-90242 is a denial of service vulnerability in Linux, published on 17 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/vt-d: Fix iopf_refcount leak on RID domain replacement

intel_iommu_attach_device() enables IOPF for the new domain but never
disables it for the old one.  device_block_translation(), called at the
start of the function, tears down translation but does not touch any IOPF
state; blocking_domain_attach_dev() has to call iopf_for_domain_remove()
explicitly before invoking it for exactly this reason.

identity_domain_attach_dev() has the same problem.  Its comment claims
that no PRI handling is needed because the device has been put in the
blocking state, but the blocking state and the IOPF reference count are
independent of each other.

As a result, replacing a domain that has an iopf_handler with another
domain at RID level leaks a reference in info->iopf_refcount.  The count
never drops back to zero, so iopf_queue_remove_device() is never called
and iommu_disable_pci_pri() triggers its WARN_ON(info->iopf_refcount)
when the device is released.

The PASID paths already handle this correctly by way of
iopf_for_domain_replace(); convert the two RID paths to do the same.
Using the replace helper rather than a bare remove keeps the enable
before the disable, so the reference count does not transiently reach
zero and evict the device from the IOPF queue.

## Which versions are affected by CVE-2026-90242?


## How do I fix CVE-2026-90242?

Apply the vendor's patch.

## Is CVE-2026-90242 being exploited?

There is no known exploitation of CVE-2026-90242 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90242 and fix it if it is affected.

What it is: CVE-2026-90242 is a denial of service vulnerability in Linux, published on 17 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-2026-90242 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-2026-90242/ (Markdown: https://insights.sbomify.com/CVE-2026-90242/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90242
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90242
- OSV: https://osv.dev/vulnerability/CVE-2026-90242

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90242/
Summaries are generated and may contain mistakes; the official description above is the record.