The Android operating system has a huge security flaw that could allow hackers to access and control mobiles just by knowing the phone number.
Zimperium, a cybersecurity firm, says an attacker could target the phone simply by sending a text message that contains a corrupted video.
Crucially, this could happen without the mobile's owner doing anything at all.
The Hangouts app on Android phones, which are owned by over 75 per cent of the world's mobile users, automatically analyses messages as they come into the phone, saving media like videos and photos for later use.
But according to Joshua Drake, a security researcher at Zimperium, this allows the hacker right in.
This happens even before the sound that you've received a message has even occurred.
That's what makes it so dangerous. [It] could be absolutely silent. You may not even see anything.