bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
{
    uint16_t old, new;
    bool v;
    /* We need to expose used array entries before checking used event. */
    smp_mb();
    /* Always notify when queue is empty (when feature acknowledge) */
    if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
        !vq->inuse && virtio_queue_empty(vq)) {
        return true;
    }

    if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
        return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
    }

    v = vq->signalled_used_valid;
    vq->signalled_used_valid = true;
    old = vq->signalled_used;
    new = vq->signalled_used = vq->used_idx;
    return !v || vring_need_event(vring_get_used_event(vq), new, old);
}

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.