The CU provides the following fixes and improvements (Referenced from https://support.microsoft.com/en-us/help/4022187/june-12-2018-cumulative-update-for-sharepoint-enterprise-server-2013)
- Allows cloud hybrid search in SharePoint 2013
The CU also installs the following security updates
- Description of the security update for SharePoint Foundation 2013: June 12, 2018 (KB4022190)
- June 12, 2018, update for SharePoint Enterprise Server 2013 (KB4022180)
- Description of the security update for SharePoint Server 2013: June 12, 2018 (KB4022179)
- Description of the security update for SharePoint Server 2013: June 12, 2018 (KB4018391)
You can download this CU from http://www.microsoft.com/downloads/details.aspx?familyid=859e1533-d392-4b71-90a0-947f2b509f5b
