An issue was discovered in Arcserve Unified Data Protection (UDP) through 6.5 Update 4. There is a DDI-VRT-2018-21 Reflected Cross-site Scripting via /authenticationendpoint/domain.jsp issue.
https://www.digitaldefense.com/blog/zero-day-alerts/arcserve-disclosure/
https://support.arcserve.com/s/article/360001392563?language=en_US