Xibo is an open source digital signage platform with a web content management system and Windows display player software. Prior to 4.4.3, missing object-level authorization on "/notification/export/{id}" allows an authenticated user to download attachments from any notification, including notifications created by administrators, by iterating over "sequential notification IDs". Exploitation requires access to the "Notification Centre" to view past notifications, a privilege granted to non-administrators as standard. This issue is fixed in version 4.4.3.