Microsoft has released May 2018 security updates and rated them as critical. Remote attacker can exploit those vulnerabilities and may be able to execute arbitrary code.
National CERT recommends all users to apply these updates.
For more details please visit https://portal.msrc.microsoft.com/en-us/security-guidance/releasenotedetail/a82328f9-1f26-e811-a968-000d3a33a34d.