Joomla! 3.6.4 – a security fix

A Joomla! 3.6.4 release containing a security fix will be published on Tuesday 25th October at approximately 14:00 UTC

Since this is a very important security fix, please be prepared to update your Joomla installation’s next Tuesday.

https://www.joomla.org/announcements/release-news/5677-important-security-announcement-pre-release-364.html