Buffer overflow in Van Dyke SecureCRT SSH client before 3.4.6, and 4.x before 4.0 beta 3, allows an SSH server to execute arbitrary code via a long SSH1 protocol version string.
http://www.vandyke.com/products/securecrt/security07-25-02.html
http://www.iss.net/security_center/static/9650.php