The remote webmail server is affected by a cross-site scripting vulnerability.
The remote host is running IceWarp Merak Mail Server, a webmail server for Windows and Linux. According to its banner, the version of IceWarp installed on the remote host is older than 9.4.0. Such versions reportedly fail to sanitize input passed to 'IMG' HTML tags in an e-mail message before displaying them. A remote attacker could leverage this issue to inject arbitrary HTML and script code into a user's browser to be executed within the security context of the affected application.
Upgrade to version 9.4.0 or higher.