void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
                                                bool with_irqfd)
{
    if (assign && !with_irqfd) {
        event_notifier_set_handler(&vq->guest_notifier, false,
                                   virtio_queue_guest_notifier_read);
    } else {
        event_notifier_set_handler(&vq->guest_notifier, false, NULL);
    }
    if (!assign) {
        /* Test and clear notifier before closing it,
         * in case poll callback didn't have time to run. */
        virtio_queue_guest_notifier_read(&vq->guest_notifier);
    }
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.