Cisco DSL CPE devices running CBOS 2.4.4 and earlier allows remote attackers to cause a denial of service (hang or memory consumption) via (1) a large packet to the DHCP port, (2) a large packet to the Telnet port, or (3) a flood of large packets to the CPE, which causes the TCP/IP stack to consume large amounts of memory.
https://exchange.xforce.ibmcloud.com/vulnerabilities/9152
http://www.securityfocus.com/bid/4815
http://www.securityfocus.com/bid/4814
http://www.securityfocus.com/bid/4813
http://www.iss.net/security_center/static/9153.php