A flaw was found in QEMU, in the virtio-scsi, virtio-blk, and virtio-crypto devices. The size for virtqueuepush as set in virtioscsicompletereq / virtioblkreqcomplete / viritocryptoreqcomplete could be larger than the true size of the data which has been sent to guest. Once virtqueuepush() finally calls dmamemoryunmap to ummap the iniov, it may call the addressspacewrite function to write back the data. Some uninitialized data may exist in the bounce.buffer, leading to an information leak.