In CORE, you have the ability to make the dashboard private or keep it public. What that means is you can share it with all or no one. However, if you share your dashboard with others, you can still restrict the dashboard or widgets seen by other users. This can be set in the Security screen > Dashboard. You can choose which widgets to show for which user, or set the modular security of the entire dashboard for them. This needs to be done individually for every user. Check CORE Help Center for details.