macOS High Sierra 10.13.2 is a free update for all customers who have a compatible machine. The update can be downloaded using the Software Update function in the Mac App Store.
macOS High Sierra 10.13.2 addresses the “Spectre” vulnerability that was publicized last week. Spectre, along with its sister vulnerability “Meltdown” are serious hardware-based exploits that take advantage of the speculative execution mechanism of a CPU, allowing hackers to gain access to sensitive information.
While Meltdown was addressed in the initial macOS High Sierra 10.13.2 update, Apple said it would introduce a mitigation for Spectre in macOS and iOS early this week. There is no hardware fix for Spectre, so Apple is addressing the vulnerability using Safari-based software workarounds.
There’s also a Safari 11.0.2 update available for macOS Sierra 10.12.6 and OS X El Capitan 10.11.6 that is designed to mitigate the effects of the Spectre vulnerability. Customers running macOS Sierra and OS X El Capitan should download the new version of Safari to make sure their machines are protected.