The Frentix GmbH OpenOlat LMS is affected by stored a Cross-Site Scripting (XSS) vulnerability. It is possible to upload files within the Media Center of OpenOlat version 18.1.5 (or lower) as an authenticated user without any other rights. Although the filetypes are limited, an SVG image containing an XSS payload can be uploaded. After a successful upload the file can be shared with groups of users (including admins) who can be attacked with the JavaScript payload.