Cisco VPN 3000 series concentrators and Cisco VPN 3002 Hardware Client 2.x.x through 3.6.7 allows remote attackers to cause a denial of service (reload) via a malformed SSH initialization packet.
https://exchange.xforce.ibmcloud.com/vulnerabilities/11955
http://www.kb.cert.org/vuls/id/317348
http://www.cisco.com/warp/public/707/cisco-sa-20030507-vpn3k.shtml