Apple has released a major set of security patches for its Mac OS X operating system.

The update fixes 25 flaws in about 20 Mac OS X operating system services and components, including the Mac's AirPort driver software, Help Viewer, and Installer application.

Some of the bugs are critical and could lead to a system crash or even allow an attacker to run unauthorised software on the Mac, Apple said in a note on the updates.

Apple recommends that all users install the update, called 2007-04, which can be found on Apple's download site.

The company has averaged one such security release per month this year, putting it on a faster update schedule than 2006, when it released a total of eight such patch sets.