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.
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d9092f52d7e61dd1557f2db2400ddb430e85937e
rhn.redhat.com/errata/RHSA-2017-0386.html
rhn.redhat.com/errata/RHSA-2017-0387.html
www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.8.7
www.openwall.com/lists/oss-security/2016/11/22/3
www.securityfocus.com/bid/94459
bugzilla.redhat.com/show_bug.cgi?id=1393350
github.com/torvalds/linux/commit/d9092f52d7e61dd1557f2db2400ddb430e85937e