Red Hat Security Advisory 2011-0919-01 - KVM is a full virtualization solution for Linux on AMD64 and Intel 64 systems. qemu-kvm is the user-space component for running virtual machines using KVM. It was found that the virtio subsystem in qemu-kvm did not properly validate virtqueue in and out requests from the guest. A privileged guest user could use this flaw to trigger a buffer overflow, allowing them to crash the guest or, possibly, escalate their privileges on the host. It was found that the virtio_queue_notify() function in qemu-kvm did not perform sufficient input validation on the value later used as an index into the array of virtqueues. An unprivileged guest user could use this flaw to crash the guest or, possibly, escalate their privileges on the host. Various other issues were also addressed.