Waline is a comment system with backend support. In versions 3.15.2 and prior, the @waline/client UserList widget builds its DOM by concatenating server-returned commenter fields directly into root.innerHTML with no HTML escaping. The commenter nick and link are stored and returned verbatim by the server (only the comment body is sanitized), and the link field is never sent to the spam filter. So an unauthenticated visitor who posts a comment with link = x"><img src=x onerror=...> achieves stored cross-site scripting that executes, with no interaction, in the browser of every visitor to a page that embeds the UserList widget. At time of publication, there are no publicly available patches.