Bug 2552198 (CVE-2026-98423)

Summary:	CVE-2026-98423 kernel: wifi: mac80211_hwsim: don't hand frames to mac80211 while stopping
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's mac80211_hwsim virtual wireless driver. A local attacker can cause a denial of service (DoS) by triggering a race condition between simulated radio shutdown and incoming network frame delivery from user space. Stopping the radio while frames are being processed triggers an unexpected kernel warning, which can lead to system instability or a kernel crash if the system is configured to halt on warnings.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-14 13:43:14 UTC

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.