XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Any user with the right to add an object on a page can execute arbitrary Groovy, Python or Velocity code in XWiki leading to full access to the XWiki installation. The root cause is improper escaping of the styles properties `FlamingoThemesCode.WebHome`. This page is installed by default. The vulnerability has been patched in XWiki versions 13.10.11, 14.4.7 and 14.10.