XWiki Platform is a generic wiki platform. Starting in versions 6.3-rc-1 and 6.2.4, it's possible to inject arbitrary wiki syntax including Groovy, Python and Velocity script macros via the `newThemeName` request parameter (URL parameter), in combination with additional parameters. This has been patched in the supported versions 13.10.10, 14.9-rc-1, and 14.4.6. As a workaround, it is possible to edit `FlamingoThemesCode.WebHomeSheet` and manually perform the changes from the patch fixing the issue.