US researchers have developed an attack named NUIT (Near-Ultrasound Inaudible Trojan) which uses the builtin microphones of your home’s Smart Assistant to silently and remotely control devices including garage door openers, smart locks and lights.
Attackers would trick victims into playing sound clips which would seem silent, as the frequencies used are almost inaudible to humans, but not to the voice assistants who will still respond to them.