The Goobi viewer is a web application that allows digitised material to be displayed in a web browser. A cross-site scripting vulnerability has been identified in Goobi viewer core prior to version 23.03 when using nicknames. An attacker could create a user account and enter malicious scripts into their profile's nickname, resulting in the execution in the user's browser when displaying the nickname on certain pages. The vulnerability has been fixed in version 23.03.