Open Ticket Request System (OTRS) before 3.0.0-beta6 adds email-notification-ext articles to tickets during processing of event-based notifications, which allows remote authenticated users to obtain potentially sensitive information by reading a ticket.
Full list of recipients from customer users in a contact field could be disclosed in notification emails event when the notification is set to be sent to each recipient individually. This issue affects: OTRS AG OTRSCustomContactFields 8.0.x version: 8.0.11 and prior versions.