Bug 2546510 (CVE-2026-98192)

Summary: CVE-2026-98192 kernel: wifi: wcn36xx: Fix potential use-after-free in TX ack timer teardown
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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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A flaw was found in the Linux kernel's wcn36xx Wi-Fi driver. This vulnerability can lead to a Denial of Service (DoS) or system instability due to a use-after-free condition. When deinitializing the transmission acknowledgement timer during device removal, the driver stops the timer without waiting for active callbacks to finish, allowing callback routines to access memory that has already been deallocated. A local user could exploit this race condition during driver teardown to crash the system.
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Description OSIDB Bzimport 2026-10-06 09:36:48 UTC 
In the Linux kernel, the following vulnerability has been resolved:

wifi: wcn36xx: Fix potential use-after-free in TX ack timer teardown

wcn36xx_dxe_deinit() tears down the TX ack timer with timer_delete(),
which only dequeues the timer and does not wait for a callback that is
already executing; the preceding free_irq() calls synchronize the
interrupt handlers only. The callback, wcn36xx_dxe_tx_timer(), can
therefore be running past the teardown and use the wcn freed along
with the ieee80211_hw in wcn36xx_remove(): it takes wcn->dxe_lock,
reads wcn->tx_ack_skb and passes wcn->hw to
ieee80211_tx_status_irqsafe().

Fix this by using timer_shutdown_sync(), which waits for a running
callback and also prevents the timer from being rearmed again. The
timer is set up again by wcn36xx_dxe_init() on the next start, so the
start/stop cycle is unaffected.

This issue was found by an in-house static analysis tool.
Comment 1 Mauro Matteo Cascella 2026-10-08 17:26:14 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98192.mbox