XWiki Rendering is vulnerable to XSS attacks through insecure XHTML syntax
The XHTML syntax depended on the xdom+xml/current syntax which allows the creation of raw blocks that permit the insertion of arbitrary HTML content including JavaScript. This allows XSS attacks for users who can edit a document like their user profile (enabled by default). The attack works by setting the document's syntax to xdom+xml/current and then inserting content like <document><p><metadata><metadata><entry><string>syntax</string><org.xwiki.rendering.syntax.Syntax><type><name>XHTML</name><id>xhtml</id><variants class="empty-list"></variants></type><version>5</version></org.xwiki.rendering.syntax.Syntax></entry></metadata></metadata></p><rawtext syntax="html/5.0" content="<script>alert(1);</script>"></rawtext></document> This has been fixed by removing the dependency …