As of May 13, 2015 it was announced that Qemu/KVM and Xen hypervisors are affected by CVE-2015-3456.
What about Virtuozzo products?
The issue CVE-2015-3456 is specific to chipset implementation in Qemu/KVM and Xen hypervisors, in the part related to the floppy disk controller.
Virtuozzo (Parallels Cloud Server) and Virtuozzo hypervisor (Parallels Server Bare Metal) use different implementation of hardware layer for virtual machines, which is not affected.
As for Virtuozzo container for Linux 4.7, it is not using any kind of hypervisor solution, and not affected too.