Apple of course has the capability to push system updates to its customers, but it has never seen the need to use its automatic, mandatory patch system -- until now.

For the first time in history, Apple has sent out an automatic security update for OS X that users have no choice whether to accept or opt out of. The security update began pushing out to OS X Mountain Lion, Mavericks and Yosemite users on Tuesday to patch what's been called a severe security flaw found in one of the most fundamental layers of the popular operating system.

The specific security flaw was unveiled publicly last week and involves one of the most basic system protocols in computing: OS X's network time protocol, or NTP.

Apple OS X uses NTP to synchronize your computer's clock and date and time settings across the Internet. It's a feature so basic to your computer, you probably haven't thought about the feature since the early 2000s, if at all.

But Apple's network time protocol -- any version of it before 4.2.8 -- can be exploited by remote very easily, allowing hackers to control Apple computers after implementing a relatively easy exploitation, the code for which of course is publicly available on the Internet.

"Exploitation of these vulnerabilities could allow an attacker to execute arbitrary code with the privileges of the [network time protocol daemon] process," warned the advisory last week, according to Ars Technica.

If you have the option to "install system data files and security updates" automatically on -- which is on by default on all OS X variants -- then you either have already received the update or will today. Look in the top right corner of your screen, your notifications drawer, or check Software Update to see if you have it.

If you're not sure if you have been pushed the patched update, go to the App Store and click on updates to download the patch as soon as possible. Unfortunately, Lion and Snow Leopard OS X systems will not get security updates, but Ars says the flaw may exist in those systems as well. For those users, it might be time to think about upgrading OS X.