WordPress 4.5.2 was issued as a security release for sites running earlier versions. It included fixes for vulnerabilities involving Plupload, used for file uploads, and MediaElement.js, used by media players.
Why the update mattered
The issues could affect older WordPress installations through specially crafted requests. Updating helped protect sites using the affected versions, so administrators were encouraged to install the release promptly.
Keep WordPress maintained
Security releases are part of routine website maintenance. Site owners should apply core updates, keep themes and plugins current, and take a backup before making changes. WordPress 4.5.2 is a historical release; current sites should use a supported WordPress version rather than installing this old version.