XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. The rollback action is missing a right protection, a user can rollback to a previous version of the page to gain rights they don't have anymore. The problem has been patched in XWiki 14.10.17, 15.5.3 and 15.8-rc-1 by ensuring that the rights are checked before performing the rollback.
