Secure Shell (SSH) 2 in Cisco IOS 12.0 through 12.3 allows remote attackers to cause a denial of service (device reload) (1) via a username that contains a domain name when using a TACACS+ server to authenticate, (2) when a new SSH session is in the login phase and a currently logged in user issues a send command, or (3) when IOS is logging messages and an SSH session is terminated while the server is sending data.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5455
https://exchange.xforce.ibmcloud.com/vulnerabilities/19990
https://exchange.xforce.ibmcloud.com/vulnerabilities/19989
https://exchange.xforce.ibmcloud.com/vulnerabilities/19987
http://www.securitytracker.com/alerts/2005/Apr/1013655.html
http://www.securityfocus.com/bid/13043
http://www.cisco.com/warp/public/707/cisco-sa-20050406-ssh.shtml