Remotely Compromising Android and iOS via a bug in Broadcom's WI-FI Chipsets

Fortunately, this is being addressed in software updates. Unfortunately, people who own older devices are left with the vulnerability forever. The iPhone 4S alone sold ~60 million units (according to Wikipedia) and did not (and most likely will not) receive any updates.

Where can you learn if your device has been patched? I have an iPhone 5S.

EDIT: From another comment [0], unfortunately if you've been holding out on updates like I have you'll have to upgrade to 10.3.3.

[0] https://support.apple.com/en-us/HT207923