Comment 7 for bug 1225276

That version isn't in the saucy repository, I manually downloaded and installed https://launchpad.net/ubuntu/trusty/amd64/openconnect/5.02-1 and https://launchpad.net/ubuntu/trusty/amd64/libopenconnect2/5.02-1

openconnect vpn...
POST https://vpn...
Attempting to connect to server ...:443
SSL negotiation with vpn...
Server certificate verify failed: signer not found

Certificate from VPN server "vpn...." failed verification.
Reason: signer not found
Enter 'yes' to accept, 'no' to abort; anything else to view: yes
Connected to HTTPS on vpn...
Got HTTP response: HTTP/1.1 302 Found
Failed to read from SSL socket: A TLS packet with unexpected length was received.
Failed to obtain WebVPN cookie

With --no-xmlpost option:
openconnect --no-xmlpost vpn...
GET https://vpn...
Attempting to connect to server ...:443
SSL negotiation with vpn.,,
Server certificate verify failed: signer not found

Certificate from VPN server "vpn..." failed verification.
Reason: signer not found
Enter 'yes' to accept, 'no' to abort; anything else to view: yes
Connected to HTTPS on vpn...
Got HTTP response: HTTP/1.1 302 Found
Failed to read from SSL socket: A TLS packet with unexpected length was received.
Failed to obtain WebVPN cookie

So both still fail with this version.