Impact A reflected cross-site scripting vulnerability (XSS) in the compare view between revisions of a page allows executing JavaScript code in the user's browser. If the current user is an admin, this can not only affect the current user but also the confidentiality, integrity and availability of the whole XWiki instance.
Patches The problem has been patched by properly escaping the URL parameters.
Workarounds The patch can be applied manually to templates/changesdoc.vm in the deployed WAR.
Attribution
XWiki thanks Mike Cole @mikecole-mg for discovering and reporting this vulnerability.