They mean just what they said: &quot;traffic directed <i>TO</i> the affected system&quot; (emphasis mine).<p>If you&#x27;re not used to dealing with routers on a regular basis, that may not make sense.<p>Then you realize that there&#x27;s also traffic <i>passing through</i> the system (i.e., being forwarded).<p>Basically, the key difference is that only UDP packets with a destination IP address belonging to the firewall can trigger the vulnerability. UDP packets with a destination IP address belonging to something else (e.g., a server behind the firewall) that simply pass through the router will not trigger it.<p>Does that help clarify it a bit?