The virtio_net_bad_features function in hw/virtio-net.c in the virtio-net driver in the Linux kernel before 2.6.26, when used on a guest OS in conjunction with qemu-kvm 0.11.0 or KVM 83, allows remote attackers to cause a denial of service (guest OS crash, and an associated qemu-kvm process exit) by sending a large amount of network traffic to a TCP port on the guest OS, related to a virtio-net whitelist that includes an improper implementation of TCP Segment Offloading (TSO).