The create_pit_timer function in arch/x86/kvm/i8254.c in KVM 83, and possibly other versions, does not properly handle when Programmable Interval Timer (PIT) interrupt requests (IRQs) when a virtual interrupt controller (irqchip) is not available, which allows local users to cause a denial of service (NULL pointer dereference) by starting a timer.

The subpage MMIO initialization functionality in the subpage_register function in exec.c in QEMU-KVM, as used in the Hypervisor (aka rhev-hypervisor) in Red Hat Enterprise Virtualization (RHEV) 2.2 and KVM 83, does not properly select the index for access to the callback array, which allows guest OS users to cause a denial of service (guest OS crash) or possibly gain privileges via unspecified vectors.

The Hypervisor (aka rhev-hypervisor) in Red Hat Enterprise Virtualization (RHEV) 2.2, and KVM 83, when the Intel VT-x extension is enabled, allows guest OS users to cause a denial of service (NULL pointer dereference and host OS crash) via vectors related to instruction emulation.

QEMU-KVM, as used in the Hypervisor (aka rhev-hypervisor) in Red Hat Enterprise Virtualization (RHEV) 2.2 and KVM 83, does not properly validate guest QXL driver pointers, which allows guest OS users to cause a denial of service (invalid pointer dereference and guest OS crash) or possibly gain privileges via unspecified vectors.