Ah, WPA2 (Wi-Fi Protected Access): you've protected our Wi-Fi so well for so many years now.
Unfortunately, that illusion of safety was shattered earlier today when security researcher Mathy Vanhoef reported a vulnerability in the WPA2 handshake protocol that he's calling KRACK (for "Key Reinstallation Attack). Since almost every modern Wi-Fi device uses it, that effectively means every modern Wi-Fi compatible device is vulnerable. You'll find more information about it in our earlier coverage.
Fortunately, Apple, Google and Microsoft have all already issued statements saying they've addressed the issue in some form or another.