The latest Firefox includes fixes for a handful of bugs, including one security vulnerability: CVE-2018-12385 (Crash in TransportSecurityInfo due to cached data).
If your installation of Firefox is configured to update itself, it will probably get around to doing that in the next few days, if it hasn’t already. You can expedite the process by starting the browser and navigating to
About Firefox in its ‘hamburger’ menu at the top right of the browser window.
The release notes for Firefox 62.0.2 provide additional details.