This will disable ssl re-negotiations and also add a TLS Renego extension in the client hello, which SSL servers like VPN 3000 concentrator will fail SSL handshake.
1) The SSLVPN client (not anyconnect client) will fail to connect after Security update.
It affects both connection to the ASA , the Cisco VPN 3000 concentrator, AND IOS routers.
ASA users can upgrade from SSL vpn client to Anyconnect and that should resolve this issue.
2) Webvpn clientless session from a browser will fail to a ASA headend running 8.2.1 to 18.104.22.168 and client certificate authenticate is enabled, with above security updates installed
3) Anyconnect weblaunch will also fail due clientless webvpn failing.
1) Upgrade client to Anyconnect client if using a ASA as the headend device. VPN 3000 concentrator does not support Anyconnect. IOS headend can be upgraded to 12.4(15)T or later which supports Anyconnect.
2) Per http://support.microsoft.com/kb/980436, you can change add this DWORD value to the windows registry and change it to a non-zero value to enable the the SSLVPN client (SVC 1.x) functionality: