# CVE-2026-98791: net/mlx5e: Fix AF_XDP TX timestamp teardown NULL dereference

> A NULL pointer dereference in the Linux kernel mlx5e driver during AF_XDP teardown can cause a system crash, requiring local access and specific network configuration.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-98791, DEBIAN-CVE-2026-98791, GHSA-5f42-c4x2-rx63, UBUNTU-CVE-2026-98791

## What is CVE-2026-98791?

CVE-2026-98791 is a vulnerability in Linux, published on 18 Oct 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:

net/mlx5e: Fix AF_XDP TX timestamp teardown NULL dereference

During XSK TX queue teardown, outstanding descriptors are completed
without a CQE. If one requested a TX timestamp, the completion path
passes that NULL CQE to mlx5e_xsk_fill_timestamp(), which dereferences
it.

Return zero when no CQE is available, indicating that teardown did not
produce a TX timestamp.

## Which versions are affected by CVE-2026-98791?


## How do I fix CVE-2026-98791?

Apply the vendor's patch.

## Is CVE-2026-98791 being exploited?

There is no known exploitation of CVE-2026-98791 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98791 and fix it if it is affected.

What it is: CVE-2026-98791 is a vulnerability in Linux, published on 18 Oct 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-2026-98791 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-2026-98791/ (Markdown: https://insights.sbomify.com/CVE-2026-98791/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98791
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98791
- OSV: https://osv.dev/vulnerability/CVE-2026-98791

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98791/
Summaries are generated and may contain mistakes; the official description above is the record.