Oracle Linux: CVE-2021-47356: ELSA-2024-12606: Unbreakable Enterprise kernel security update (IMPORTANT) (Multiple Advisories)

In the Linux kernel, the following vulnerability has been resolved:
mISDN: fix possible use-after-free in HFC_cleanup()
This module's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.
Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.
A vulnerability was found in the Linux kernel's mISDN driver. This issue arises during the cleanup process, where a timer handler might still be running after the driver has been removed, which can lead to a use-after-free issue, potentially causing a system crash.