Open-Xchange AppSuite before 7.0.2 rev14, 7.2.0 before rev11, 7.2.1 before rev10, and 7.2.2 before rev9 relies on user-supplied data to predict the IMAP server hostname for an external domain name, which allows remote authenticated users to discover e-mail credentials of other users in opportunistic circumstances via a manual-mode association of a personal e-mail address with the hostname of a crafted IMAP server.