Comment by miduil
6 hours ago
the session (or pairing key) means you can both connect to the headphone or impersonate it.
It can toggle the hands-free mode and listen to whatever is being talked, you'd notice that it has switched to the mode though - but if you're headphones are powered on and you're not listening to in they can be used for eavesdropping.
During the talk they both demonstrate listening to the microphone and also receiving a WhatsApp 2FA call.
presumably, even in hands-free mode the attacker needs to be very close to the speaker to hear it