Reducing severity as this is only reflected if the user inputs html in either the default value or the validator, and there is a validation error preventing it from being saved.
Created redmine issue http://projects.theforeman.org/issues/16020 from this bug
Moving to POST since upstream bug http://projects.theforeman.org/issues/16020 has been closed
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2018:0336