IMPORTANT WORDPRESS USERS
Today, a significant SQL-Injection vulnerability was fixed in WordPress 4.8.3. Before reading further, if you haven’t updated yet stop right now and update.
This is a security release for all previous versions and we strongly encourage you to update your sites immediately.
WordPress versions 4.8.2 and earlier are affected by an issue where
$wpdb->prepare() can create unexpected and unsafe queries leading to potential SQL injection (SQLi). WordPress core is not directly vulnerable to this issue, but they've added hardening to prevent plugins and themes from accidentally causing a vulnerability.