Cisco Security Advisory – Cisco Internetwork Operating System (IOS) Software release trains 12.2T, 12.3 and 12.3T may contain vulnerabilities in processing certain Internet Key Exchange (IKE) Xauth messages when configured to be an Easy VPN Server. Successful exploitation of these vulnerabilities may permit an unauthorized user to complete authentication and potentially access network resources.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/37035/cisco-sa-20050406-xauth.txt
Source: https://packetstormsecurity.com/files/37035/Cisco-Security-Advisory-20050406-xauth.html