Remote code execution in xwiki-platform

XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. In affected versions it's possible for an unprivileged user to perform a remote code execution by injecting a groovy script in her own profile and by calling the Reset password feature since the feature is performing a save of the user profile with programming rights in the impacted versions of XWiki. The issue has been patched in XWiki 13.1RC1. There are two different possible workarounds, each consisting of modifying the XWiki/ResetPassword page. 1. The Reset password feature can be entirely disabled by deleting the XWiki/ResetPassword page. 2. The script in XWiki/ResetPassword can also be modified or removed: an administrator can replace it with a simple email contact to ask an administrator to reset the password.