# CVE-2025-38594: iommu/vt-d: Fix UAF on sva unbind with pending IOPFs

> A use-after-free in the Linux kernel IOMMU driver allows local attackers to trigger a kernel panic, causing denial of service.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 19 Aug 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-38594, GHSA-3p7j-wq4m-3p8j, UBUNTU-CVE-2025-38594

## What is CVE-2025-38594?

CVE-2025-38594 is a high-severity use after free vulnerability in Linux kernel, published on 19 Aug 2025. 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 UAF on sva unbind with pending IOPFs

Commit 17fce9d2336d ("iommu/vt-d: Put iopf enablement in domain attach
path") disables IOPF on device by removing the device from its IOMMU's
IOPF queue when the last IOPF-capable domain is detached from the device.
Unfortunately, it did this in a wrong place where there are still pending
IOPFs. As a result, a use-after-free error is potentially triggered and
eventually a kernel panic with a kernel trace similar to the following:

 refcount_t: underflow; use-after-free.
 WARNING: CPU: 3 PID: 313 at lib/refcount.c:28 refcount_warn_saturate+0xd8/0xe0
 Workqueue: iopf_queue/dmar0-iopfq iommu_sva_handle_iopf
 Call Trace:
   <TASK>
   iopf_free_group+0xe/0x20
   process_one_work+0x197/0x3d0
   worker_thread+0x23a/0x350
   ? rescuer_thread+0x4a0/0x4a0
   kthread+0xf8/0x230
   ? finish_task_switch.isra.0+0x81/0x260
   ? kthreads_online_cpu+0x110/0x110
   ? kthreads_online_cpu+0x110/0x110
   ret_from_fork+0x13b/0x170
   ? kthreads_online_cpu+0x110/0x110
   ret_from_fork_asm+0x11/0x20
   </TASK>
  ---[ end trace 0000000000000000 ]---

The intel_pasid_tear_down_entry() function is responsible for blocking
hardware from generating new page faults and flushing all in-flight
ones. Therefore, moving iopf_for_domain_remove() after this function
should resolve this.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-38594?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38594?

Apply the vendor's patch.

## Is CVE-2025-38594 being exploited?

There is no known exploitation of CVE-2025-38594 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38594 and fix it if it is affected.

What it is: CVE-2025-38594 is a high-severity use after free vulnerability in Linux kernel, published on 19 Aug 2025. 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-2025-38594 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-38594/ (Markdown: https://insights.sbomify.com/CVE-2025-38594/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38594
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38594
- OSV: https://osv.dev/vulnerability/CVE-2025-38594

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38594/
Summaries are generated and may contain mistakes; the official description above is the record.