# CVE-2026-74306: vfio/qat: fix f_pos race in qat_vf_resume_write()

> A race condition in the Linux kernel's vfio/qat driver allows concurrent writers to bypass bounds checks, potentially leading to memory corruption and privilege escalation.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74306, DEBIAN-CVE-2026-74306, GHSA-5q42-qm7h-h2q2, UBUNTU-CVE-2026-74306

## What is CVE-2026-74306?

CVE-2026-74306 is a high-severity vulnerability in Linux, published on 15 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:

vfio/qat: fix f_pos race in qat_vf_resume_write()

qat_vf_resume_write() checks filp->f_pos before taking migf->lock, but
copies into the migration-state buffer after taking the lock and
re-reading the shared file position.

Two concurrent writers could therefore pass the bounds check with the
old offset, then have the second writer copy after the first advanced
f_pos, writing past the end of the migration-state buffer.

Take migf->lock before doing the boundary checks.

## Which versions are affected by CVE-2026-74306?


## How do I fix CVE-2026-74306?

Apply the vendor's patch.

## Is CVE-2026-74306 being exploited?

There is no known exploitation of CVE-2026-74306 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74306 and fix it if it is affected.

What it is: CVE-2026-74306 is a high-severity vulnerability in Linux, published on 15 Aug 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-2026-74306 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-2026-74306/ (Markdown: https://insights.sbomify.com/CVE-2026-74306/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74306
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74306
- OSV: https://osv.dev/vulnerability/CVE-2026-74306

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74306/
Summaries are generated and may contain mistakes; the official description above is the record.