The remote host is vulnerable to an HTML Injection attack
The version of CommuniGate Pro running on the remote host is prone to an HTML injection flaw. The root cause of this flaw is a failure within the CommuniGate software when processing a specially formatted URI. An attacker, exploiting this flaw, would need to be able to entice a user into opening an email. Upon opening the email, the attacker would be able to execute arbitrary script code.
Upgrade to CommuniGate Pro 5.2.15 or newer.