Last week, Apple issued security updates to patch a flaw affecting iPhone and iPad users that could enable bad actors – using a piece of espionage software called "Pegasus" – to gain control of users' devices and enlist them as spying machine. Because much of the same codebase is used across Apple's platforms, the company released security updates yesterday to address a similar bug detected in its desktop OS.

This latest security patch fixes the operating systems of El Capitan and Yosemite Mac, as well as the company's web browser Safari.

Security Update 2016-001 for OS X El Capitan users and Security Update 2016-005 for OS X Yosemite users updates security for the operating system. The update to the browser, which fixes a memory corruption issue, advances the Safari browser to v9.1.3 to block the launch of arbitrary code (read: malware).

Apple is advising users to upgrade systems immediately.