Version 6 has fewer features (the bug is in a new feature that only exists in Java 7) and Security Explorations found they could not (yet at least) break it.

For example, choose "Java SE 6" if you want to download any version number ranging from Java 6.0 to Java 6.43. You will select the specific update number on the next page.

You can check which Java version is on your Mac to see if you have the most up-to-date Java running, or you can check on the Java website.