Quote Originally Posted by Softpedia
The exploit was first spotted by F-Secure’s Timo Hirvonen, a few days after the proof-of-concept for CVE-2013-2463 was made public. Furthermore, the researcher says the Java zero-day exploit has been integrated into the Neutrino exploit kit.

Experts from Qualys warn that this guarantees a widespread adoption.
Full article here.

The exploit affects Java 1.7 Update 21 and older. Those who have Java installed due to our chat system or for other purposes are advised to update it to the latest version. Sadly, versions prior to Java 1.7 will not be updated, since Oracle doesn't publicly (Java 1.6 Update 51 issues the patch, but it's available to paying customers only) support them anymore. Users with Java installed, but don't use it are advised to uninstall the software altogether, due to the many implementation and security issues.