application-urlshortener create shortened URLs for XWiki pages. Versions prior to 1.2.4 are vulnerable to users with view access being able to create arbitrary pages. Any user (even guests) can create these docs, even if they don't exist already. This can enable guest users to denature the structure of wiki pages, by creating 1000's of pages with random name, that then become very difficult to handle by admins. Version 1.2.4 fixes the issue. No known workarounds are available.
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.