These people were actually trying to connect to port 8080 on their localhost, and not on a another device, but the behavior they reported was identical to this issue. When I tried it on my work Mac (which has the Cisco VPN client), I could not get anywhere, even from Windows on Parallels. When I tried it on my personal Mac, it worked without any problems.
It may not be the same thing, but I thought this might help someone.
"23-nov-15, twitter. Cisco @AnyConnect" wrote: There were some bugs in old versions where Web Security was used if installed but not configured. Make sure you don't deploy the web security module if not using it and/or upgrade to current AC patch versions.