Multiple race conditions in HtmlCleaner before 2.6, as used in Open-Xchange AppSuite 7.2.2 before rev13 and other products, allow remote authenticated users to read the private e-mail of other persons in opportunistic circumstances by leveraging lack of thread safety and performing a rapid series of (1) mail-sending or (2) draft-saving operations.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2013-4877
http://sourceforge.net/p/htmlcleaner/bugs/86/
http://archives.neohapsis.com/archives/bugtraq/2013-08/0115.html