Xen in the Linux kernel, when running a guest on a host without hardware assisted paging (HAP), allows guest users to cause a denial of service (invalid pointer dereference and hypervisor crash) via the SAHF instruction.

The ioapic_deliver function in virt/kvm/ioapic.c in the Linux kernel through 3.14.1 does not properly validate the kvm_irq_delivery_to_apic return value, which allows guest OS users to cause a denial of service (host OS crash) via a crafted entry in the redirection table of an I/O APIC. NOTE: the affected code was moved to the ioapic_service function before the vulnerability was announced.

The get_rx_bufs function in drivers/vhost/net.c in the vhost-net subsystem in the Linux kernel package before 2.6.32-431.11.2 on Red Hat Enterprise Linux (RHEL) 6 does not properly handle vhost_get_vq_desc errors, which allows guest OS users to cause a denial of service (host OS crash) via unspecified vectors.

The do_block_io_op function in (1) drivers/xen/blkback/blkback.c and (2) drivers/xen/blktap/blktap.c in Xen before 3.4.0 for the Linux kernel 2.6.18, and possibly other versions, allows guest OS users to cause a denial of service (infinite loop and CPU consumption) via a large production request index to the blkback or blktap back-end drivers. NOTE: some of these details are obtained from third party information.