Oracle has rush-released a fix for a widely-reported major security flaw in Java which renders browser users vulnerable to attacks . Here's how to install it.
To update, hit the Java site and download a fresh Java installation. Take care when clicking through the installer; it will try and install an unwanted Ask.com crapware toolbar as well. Make sure you untick that option.
If you're on Windows have automatic updates enabled for Java, you will receive these updates automatically. Follow the steps above to speed up the process. The blog post below links to resources for updating more complex Java installations.
Security Alert for CVE-2013-0422 Released [The Oracle Software Security Assurance Blog]