16 October

When your phone joins a Wi-Fi network with a password, the data between the phone and the wireless access point (the router) is encrypted, most commonly with the WPA2 standard or the newer WPA3. On 16 October 2017, a researcher disclosed KRACK, a weakness in WPA2 that lets an attacker within Wi-Fi range read information that was assumed to be encrypted. The researcher's website reads that the weakness is in the Wi-Fi standard itself, that any device supporting Wi-Fi is most likely affected, and that changing the Wi-Fi password does not prevent the attack. Android's November 2017 security bulletin and Apple's iOS 11.1, released at the end of October 2017, both carry fixes, and the website reads that home routers are mostly not affected, though it still recommends updating router firmware. Readers still using an old phone can check in Settings whether the Android security patch level is 6 November 2017 or later, and on an iPhone whether iOS is 11.1 or later.