We have released 2.3 to the community and all our support efforts are now transitioned to 2.3. Also, BigBlueButton 2.2 is running on Ubuntu 16.04 which is now end of life.
As such, we highly recommend that all administrators deploy 2.3 going forward as it is built upon Ubuntu 18.04. You'll find [many improvements](/2.3/new.html) in this newer version.
If you believe you have found a security vunerability in BigBlueButton please let us know directly by e-mailing security@bigbluebutton.org with as much detail as possible.