https://wordpress.org/news/2018/04/wordpress-4-9-5-security-and-maintenance-release/
WordPress 4.9.5 is now available. This is a security and maintenance release for all versions since WordPress 3.7. We strongly encourage you to update your sites immediately.
WordPress versions 4.9.4 and earlier are affected by three security issues. As part of the core team’s ongoing commitment to security hardening, the following fixes have been implemented in 4.9.5:
Don’t treat localhost
Source: Security Feed