NetBSD 3.0, 3.1, and 4.0, when a pppoe instance exists, does not properly check the length of a PPPoE packet tag, which allows remote attackers to cause a denial of service (system crash) via a crafted PPPoE packet.
https://exchange.xforce.ibmcloud.com/vulnerabilities/44679
http://www.vupen.com/english/advisories/2009/0633
http://www.securitytracker.com/id?1020749
http://www.securityfocus.com/bid/30838