Text injection/Content Spoofing in 404 page in Zammad 1.0.x up to 4.0.0 could allow remote attackers to manipulate users into visiting the attackers' page.
Cross Site Scripting (XSS) in Zammad 1.0.x up to 4.0.0 allows remote attackers to execute arbitrary web script or HTML via multiple models that contain a 'note' field to store additional information.
An issue was discovered in Zammad before 3.4.1. There are wrong authorization checks for impersonation requests via X-On-Behalf-Of. The authorization checks are performed for the actual user and not the one given in the X-On-Behalf-Of header.