CVE-2026-98423: wifi: mac80211_hwsim: don't hand frames to mac80211 while stopping
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211hwsim: 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 WARNON(!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.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
Systems using the Linux kernel's mac80211_hwsim component and receiving frames from wmediumd are exposed to the race condition.
What conditions are required to trigger the warning?
A frame from wmediumd must pass the started-state check while the simulated radio is running, and the radio must then be stopped before mac80211 receives that frame.
What is the observable effect?
The race can cause mac80211 to hit WARN_ON(!local->started) while handling a frame for a stopped radio.
What does the fix change?
The fix expands mutex protection so frame delivery from wmediumd is synchronized with radio shutdown, preventing delivery after the radio has stopped.