The x86_decode_insn function in arch/x86/kvm/emulate.c in the Linux kernel before 4.8.7, when KVM is enabled, allows local users to cause a denial of service (host OS crash) via a certain use of a ModR/M byte in an undefined instruction. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8630