cPanel does not do anything to the Virtuozzo/OpenVZ kernel or the iptables modules (which are kernel modules). cPanel specifically excludes the kernel from yum updates, in fact. You really need to talk to your VPS administrator about this or, if you are the VPS administrator, consult the Virtuozzo/OpenVZ documentation. This is not something that cPanel has any control over and not something that cPanel support can help you with.
Your best resources for help with this would be a forum that specializes in OpenVZ/Virtuozzo, the OpenVZ/Virtuozzo documentation, or a qualified administrator who is familiar with administration of this VPS environment.