Oracle has fixed 14 security holes in Java that affects all users. The vulnerabilities allow attackers to use specially crafted Java WebStart applications or web services in order to install malicious code on computers that run flawed versions of Java. This is a pretty typical update and you can download it automatically through your updater or from Majorgeeks at:

Sun Java Runtime Environment 6 Update 31

Sun Java Runtime Environment 7 Update 3

Most users will be running version 6.x.

If you want to get geeky with it, you can read:

Text Form of Oracle Java SE Critical Patch Update here.