static inline void ne2000_dma_update(NE2000State *s, int len)
{
    s->rsar += len;
    /* wrap */
    /* XXX: check what to do if rsar > stop */
    if (s->rsar == s->stop)
        s->rsar = s->start;

    if (s->rcnt <= len) {
        s->rcnt = 0;
        /* signal end of transfer */
        s->isr |= ENISR_RDC;
        ne2000_update_irq(s);
    } else {
        s->rcnt -= len;
    }
}

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.