As much as Apple would like you to think otherwise, their products are not immune to security vulnerabilities. If you use OS X Mavericks or iTunes, you'd best update.
This week, Apple released two security updates to fix vulnerabilities in OS X Mavericks and iTunes. The updates fix a wide range of vulnerabilities, including memory corruption flaws attackers could use to execute code. If you use OS X Mavericks or iTunes, you should download and install Apple's updates immediately, or let their automatic Software Updater do it for your.
See the links below for more information about each update:
If you'd like to keep up with Apple's latest security updates, be sure to bookmark their Security page, and you can find links to all their patches on the Download page.