Ipswitch IMail contains a flaw withing the web messaging functionality that may allow a remote denial of service. The issue is triggered when a a user creates a specially crafted email with an overly long 'To:' field, and will result in loss of availability for the server.
Remote / Network Access
Loss of Availability
Upgrade to version 8.13 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.