The instruction decoder in arch/x86/kvm/emulate.c in the KVM subsystem in the Linux kernel before 3.18-rc2 does not properly handle invalid instructions, which allows guest OS users to cause a denial of service (NULL pointer dereference and host OS crash) via a crafted application that triggers (1) an improperly fetched instruction or (2) an instruction that occupies too many bytes. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-8480.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=a430c9166312e1aa3d80bce32374233bdbfeba32
secunia.com/advisories/62042
thread.gmane.org/gmane.comp.emulators.kvm.devel/128427
www.openwall.com/lists/oss-security/2014/10/23/7
bugzilla.redhat.com/show_bug.cgi?id=1156615
github.com/torvalds/linux/commit/a430c9166312e1aa3d80bce32374233bdbfeba32