Bug 2536547 (CVE-2026-93149)

Summary: CVE-2026-93149 kernel: wifi: mac80211_hwsim: avoid NULL skb in stop queue drain
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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   
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Doc Text:
A flaw was found in the Linux kernel's mac80211_hwsim component. A race condition exists in the `mac80211_hwsim_stop()` function. This condition occurs when a network packet (skb) is removed from a queue after it has been checked for emptiness but before it is actually dequeued. This can lead to a null pointer being passed to `ieee80211_free_txskb()`, potentially causing a system crash and a denial of service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-17 18:22:02 UTC 
In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211_hwsim: avoid NULL skb in stop queue drain

mac80211_hwsim_stop() drops any frames left in data->pending. The loop
currently checks skb_queue_empty() and then dequeues separately.

That split is racy with TX status handling, which can remove a pending
frame under the queue lock. If the last entry is removed after the empty
check, skb_dequeue() returns NULL and the stop path passes that NULL skb
to ieee80211_free_txskb().

Use skb_dequeue() as the loop condition instead. The dequeue result is the
object that stop owns and frees, and a concurrent status completion that
empties the queue simply makes the loop terminate.
Comment 1 gkamathe 2026-09-18 20:54:17 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93149.mbox