Medium [CVE-2026-68198] Linux kernel: Use-after-free in ath6kl Wi-Fi driver leading to denial of service

In the Linux kernel, the following vulnerability has been resolved: wifi: ath6kl: fix use-after-free in aggr_reset_state() The aggr_reset_state() function uses timer_delete() (non-synchronous) for the aggregation timer before proceeding to delete TID state and before the structure is freed by callers like aggr_module_destroy().

If the timer callback (aggr_timeout) is executing when aggr_reset_state() is called, the callback will continue to access aggr_conn fields like rx_tid[] and stat[] which may be freed immediately after by kfree(aggr_info->aggr_conn) in aggr_module_destroy().

Additionally, the timer callback can re-arm itself via mod_timer() while aggr_reset_state() is running, creating a more complex race condition. Use timer_delete_sync() instead to ensure any running timer callback has completed before returning.

This occurs because a non-synchronous timer deletion allows a timer callback (`aggr_timeout`) to access memory that has already been freed, creating a race condition. An attacker could potentially exploit this to cause system instability or a denial of service.

Red Hat severity: Important — CVSS 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-825.

Affected Red Hat products: Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat OpenShift Container Platform 4.