as far as I understand from the FAQ page, as long as connections to your PG database are blocked from external sources, you should be safe. Seems like a good idea to upgrade as soon as possible anyway though.
> How can users protect themselves?
> * Download the update release and update all of your servers as soon as possible.
> * Ensure that PostgreSQL is not open to connections from untrusted networks.
> * Audit your database users to be certain that all logins require proper credentials, and that the only logins which exist are legitimate and in current use.