XPlatform Wiki vulnerable to cross-site scripting via xcontinue parameter in preview actions template

XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Users are able to forge an URL with a payload allowing to inject Javascript in the page (XSS). It's possible to exploit the previewactions template to perform a XSS, e.g. by using URL such as: > <hostname>/xwiki/bin/get/FlamingoThemes/Cerulean xpage=xpart&vm=previewactions.vm&xcontinue=javascript:alert(document.domain). This vulnerability exists since XWiki 6.1-rc-1. The vulnerability has been patched in XWiki 14.10.5 and 15.1-rc-1.