Imagine if anyone could punch in a phone number from the largest U.S. cell carrier and instantly retrieve a list of its recent incoming calls—complete with timestamps—without compromising the device, guessing a password, or alerting the user.Now imagine that number belongs to a journalist, a police officer, a politician, or someone fleeing an abuser.This capability wasn’t a hypothetical.I recently identified a security vulnerability in the Verizon Call Filter iOS app which made it possible for a...