A flaw was found in foreman from versions 1.18. A stored cross-site scripting vulnerability exists due to an improperly escaped HTML code in the breadcrumbs bar. This allows a user with permissions to edit which attribute is used in the breadcrumbs bar to store code that will be executed on the client side.
https://projects.theforeman.org/issues/25169
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-14664