# CVE-2026-98423: wifi: mac80211_hwsim: don't hand frames to mac80211 while stopping

> A race condition in the Linux kernel mac80211_hwsim module allows local attackers to trigger a kernel warning and potential denial of service.

- **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:** 14 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-108153, BELL-CVE-2026-98423, DEBIAN-CVE-2026-98423, GHSA-gc6m-v2g5-2jw7, UBUNTU-CVE-2026-98423

## What is CVE-2026-98423?

CVE-2026-98423 is a vulnerability in Linux, published on 14 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:

wifi: mac80211_hwsim: don't hand frames to mac80211 while stopping

The code checks ->started for frames coming from wmediumd, but the
radio can be stopped after the check and before frame delivery,
causing mac80211 to hit the WARN_ON(!local->started).

Expand the mutex for this case and synchronise against it when the
radio is stopped to avoid being able to hit the warning with hwsim.

Drop the error print that would've complicated the error path, it
only triggers for allocation failures (already noisy) and malformed
frames anyway.

## Which versions are affected by CVE-2026-98423?


## How do I fix CVE-2026-98423?

Apply the vendor's patch.

## Is CVE-2026-98423 being exploited?

There is no known exploitation of CVE-2026-98423 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98423 and fix it if it is affected.

What it is: CVE-2026-98423 is a vulnerability in Linux, published on 14 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-2026-98423 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-2026-98423/ (Markdown: https://insights.sbomify.com/CVE-2026-98423/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98423
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98423
- OSV: https://osv.dev/vulnerability/CVE-2026-98423

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98423/
Summaries are generated and may contain mistakes; the official description above is the record.