Without the patch, a hacker could be what experts call a man-in-the-middle — it’s like a game of Telephone you don’t even know you’re playing.

“Alice wants to communicate securely with Bob,” explained Nathan Sportsman, a mobile security expert and CEO of Praetorian. But Eve, a hacker, uses this vulnerability to put herself between the two. “Now Alice is talking to Eve and Eve is talking to Bob,” he explained. Alice and Bob think they’re talking to each other privately.

This lets hackers view the communications, such as bank deposits or Facebook (FB, Fortune 500) posts. If they intercept a username and password, the hacker could return to your account later and cause more damage, Sportsman said.