Apple has released the iOS 11.2.2 update today for iPhone and iPad. The update contains a fix for the Spectre flaw and is recommended for all users.
Security Notes
- Available for: iPhone 5s and later, iPad Air and later, and iPod touch 6th generation
- Description: iOS 11.2.2 includes security improvements to Safari and WebKit to mitigate the effects of Spectre (CVE-2017-5753 and CVE-2017-5715).
We would like to acknowledge Jann Horn of Google Project Zero; and Paul Kocher in collaboration with Daniel Genkin of University of Pennsylvania and University of Maryland, Daniel Gruss of Graz University of Technology, Werner Haas of Cyberus Technology, Mike Hamburg of Rambus (Cryptography Research Division), Moritz Lipp of Graz University of Technology, Stefan Mangard of Graz University of Technology, Thomas Prescher of Cyberus Technology, Michael Schwarz of Graz University of Technology, and Yuval Yarom of University of Adelaide and Data61 for their assistance.
Aside from iOS, there is also a supplemental update for macOS. You should download both as soon as you can.