XWiki Platform is a generic wiki platform. Starting in version 5.4.4 and prior to versions 14.4.8, 14.10.4, and 15.0, a stored cross-site scripting vulnerability can be exploited by users with edit rights by adding a `AppWithinMinutes.FormFieldCategoryClass` class on a page and setting the payload on the page title. Then, any user visiting `/xwiki/bin/view/AppWithinMinutes/ClassEditSheet` executes the payload. The issue has been patched in XWiki 14.4.8, 14.10.4, and 15.0. As a workaround, update `AppWithinMinutes.ClassEditSheet` with a patch.
https://jira.xwiki.org/browse/XWIKI-20365
https://github.com/xwiki/xwiki-platform/security/advisories/GHSA-4wc6-hqv9-qc97