Along with the four patches, Apple also yanked Adobe's Flash Player from Safari if the plug-in was older than version 10.1.102.64, which released in November 2010. Since then, Adobe has shipped Flash Player 11 for the Mac. It has also continued to maintain the older version 10, which now stands at version 10.3.183.19.

"This update disables Adobe Flash Player if it is older than 10.1.102.64 by moving its files to a new directory," Apple's stated Wednesday. "This update presents the option to install an updated version of Flash Player from the Adobe website."

Apple stopped bundling Flash Player with OS X in the fall of 2010, but users have been free to download and install the plug-in on their own. Microsoft last distributed Flash with the nearly-11-year-old Windows XP. Neither Windows Vista or Windows 7 included a preinstalled version of Adobe's software.

Blocking Flash was the second such move by Apple in a month: On April 12, the company issued an OS X update that of Java applets by the Java browser plug-in. Apple took the step because of Flashback, a malware family that used a Java vulnerability to infect hundreds of thousands of Macs in a spree that still continues.

"As a security hardening measure, the Java browser plug-in and Java Web Start are deactivated if they are unused for 35 days," Apple said at the time.