Following reports that a major security flaw has been discovered in Java browser plugins, Apple has taken quick action to limit the number of users that it could potentially affect on the Mac. The company has released an update which limits the behavior of the Java Applet plugin until a fix for the security flaw can be found. The update is run through the anti-malware capabilities within the OS X operating system that allows the blacklisting of malicious software.
Java isn’t installed on all Macs, as users now have to install the plugin manually ever since Apple stopped shipping Java as a default plugin with all Macs. The OS X anti-malware system is updated daily, so if the the Java browser plugin is installed on a Mac, the blocking of the applet will be done automatically, and users do not physically need to install an update.
You can read more on the vulnerability at the NIST National Vulnerability Database website.