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

Summary

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.

Timeline

1. Oct 6, 2026, 8:44 AM UTCCVE published
2. Oct 21, 2026, 12:54 PM UTCRecord last updated

Affected versions

• Linux Linux

  From fdf21cc3714939dd4327f3d664fe5863d15ccb31 · fixed in 15e59e377facc87ce82228279d88efaa89fdbca5; From fdf21cc3714939dd4327f3d664fe5863d15ccb31 · fixed in 3edabc965bcce49cbb2ec1c2b91f8a555a8ec8bd; From fdf21cc3714939dd4327f3d664fe5863d15ccb31 · fixed in 2bddc5d088cf430ecd913020472f1def32a36a3d; From fdf21cc3714939dd4327f3d664fe5863d15ccb31 · fixed in c0df0878e9110909cf0bec6080d72d36401a0c89; From fdf21cc3714939dd4327f3d664fe5863d15ccb31 · fixed in d9be5e75530772fc31637070d51e5717d6aeaa2a

• Linux Linux

  5.10

• KernelLinux

  From 5.10.0 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.54; From 6.19.0 · fixed in 7.2.8

References 5