The WRMSR processing functionality in the KVM subsystem in the Linux kernel through 3.17.2 does not properly handle the writing of a non-canonical address to a model-specific register, which allows guest OS users to cause a denial of service (host OS crash) by leveraging guest OS privileges, related to the wrmsr_interception function in arch/x86/kvm/svm.c and the handle_wrmsr function in arch/x86/kvm/vmx.c.

arch/x86/kvm/vmx.c in the KVM subsystem in the Linux kernel before 3.17.2 on Intel processors does not ensure that the value in the CR4 control register remains the same after a VM entry, which allows host OS users to kill arbitrary processes or cause a denial of service (system disruption) by leveraging /dev/kvm access, as demonstrated by PR_SET_TSC prctl calls within a modified copy of QEMU.