https://arstechnica.com/gadgets/2018/01/ios-and-macos-updates-available-now-address-spectre-vulnerabilities/

Metldown and Spectre security risks affecting nearly every modern processor came to light last week, and now Apple has released a pair of software updates to address the Spectre vulnerability. iOS 11.2.2 and macOS High Sierra 10.13.2, while sparse in detail, are both now available for free on compatible devices.