Race condition in kernel/events/core.c in the Linux kernel before 4.4 allows local users to gain privileges or cause a denial of service via use-after-free vulnerability by leveraging incorrect handling of an swevent data structure during a CPU unplug operation.
Removing a CPU is a privileged operation and not possible by normal users. This flaw should not affect many individuals.
This issue affects the Linux kernel shipping with Red Hat Enterprise Linux 6. Future updates for the respective releases may address the issue.
This issue does not not affect Red Hat Enterprise Linux 5, 7, MRG-2 kernels.
This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates of Red Hat Enterprise Linux 5. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
A possible mitigation is to only remove CPU's while the system is shut down. This will prevent local attackers from being able to abuse this flaw.