The frontend component in Open-Xchange OX App Suite before 7.6.3-rev31, 7.8.x before 7.8.2-rev31, 7.8.3 before 7.8.3-rev41, and 7.8.4 before 7.8.4-rev20 allows remote attackers to spoof the origin of e-mails via unicode characters in the "personal part" of a (1) From or (2) Sender address.