This update was released on October 17th 2018 at 16:42 UTC (SA-CORE-2018-006) and it is critical as it fixes the issue when content moderation fails to check user access privileges to use some transitions and that is a direct road to access bypass. For those who runs Drupal 7 update version is 7.6.0 for, version 8.5.x or earlier, upgrade to Drupal 8.5.8, for version 8.6.x, upgrade to 8.6.2. This is a routine update from technical point of view and main reason for it is security. Your Drupal website needs to be updated right away, remember to backup data base before you proceed. Check instructions if you have doubts and secure your site today, secure it now.