In the Linux kernel, the following vulnerability has been resolved:

watchdog: cpu5wdt.c: Fix use-after-free bug caused by cpu5wdt_trigger

When the cpu5wdt module is removing, the origin code uses del_timer() to
de-activate the timer. If the timer handler is running, del_timer() could
not stop it and will return directly. If the port region is released by
release_region() and then the timer handler cpu5wdt_trigger() calls outb()
to write into the region that is released, the use-after-free bug will
happen.

Change del_timer() to timer_shutdown_sync() in order that the timer handler
could be finished before the port region is released.

kernel.org https://git.kernel.org/stable/c/573601521277119f2e2ba5f28ae6e87fc594f4d4 [No types assigned]

kernel.org https://git.kernel.org/stable/c/9b1c063ffc075abf56f63e55d70b9778ff534314 [No types assigned]

kernel.org https://git.kernel.org/stable/c/f19686d616500cd0d47b30cee82392b53f7f784a [No types assigned]