Open Ticket Request System (OTRS) 4.0.x before 4.0.33 and 5.0.x before 5.0.31 allows an admin to conduct an XSS attack via a modified URL because user and customer preferences are mishandled.
https://lists.debian.org/debian-lts-announce/2018/11/msg00028.html
https://community.otrs.com/security-advisory-2018-09-security-update-for-otrs-framework/