Important Mac OS X Security Updates
If you are using Mac OS 10.9 Mavericks, 10.8 Mountain Lion, or 10.7 Lion, you should download and apply any updates that are available to protect yourself from new security vulnerabilities. Last week, Apple released several security updates for OS X, which patched known vulnerabilities in their operating system and the Safari web browser. A security update was also released for iOS 7 and Quicktime for Windows.
To check for the latest software updates on your Mac, choose the Apple menu (in the upper-left corner) > Software Update.
(H/T Jay Lindly)