MailEnable before 8.60 allows Stored XSS via malformed use of "<img/src" with no ">" character in the body of an e-mail message.
https://www.nccgroup.trust/uk/our-research/multiple-vulnerabilities-in-mailenable/
https://web.archive.org/web/20150329173628/http://www.mailenable.com/Standard-ReleaseNotes.txt