CVE-2026-98192wifi: wcn36xx: Fix potential use-after-free in TX ack timer teardown

Official description

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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/915298dbb766d2311b0822ab6ef24780def0bd53
• https://git.kernel.org/stable/c/e7f265d507ee55017b67ef4722df884468be1113
• https://git.kernel.org/stable/c/7ce1e55a439968a298a63d3199cb1c2636429746
• https://git.kernel.org/stable/c/15e59e377facc87ce82228279d88efaa89fdbca5
• https://git.kernel.org/stable/c/3edabc965bcce49cbb2ec1c2b91f8a555a8ec8bd
• https://git.kernel.org/stable/c/2bddc5d088cf430ecd913020472f1def32a36a3d
• https://git.kernel.org/stable/c/c0df0878e9110909cf0bec6080d72d36401a0c89
• https://git.kernel.org/stable/c/d9be5e75530772fc31637070d51e5717d6aeaa2a