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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
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.
Sources
Also known as AZL-108153, BELL-CVE-2026-98423, DEBIAN-CVE-2026-98423, GHSA-gc6m-v2g5-2jw7, UBUNTU-CVE-2026-98423.