A newly-discovered security flaw affects virtually every Wi-Fi device, and could render your home network as readable to hackers as the free Wi-Fi at a coffee shop.

Belgian Researcher Mathy Vanhoef has detailed a method of breaking WPA2, the security protocol used by the large majority of routers and devices to secure internet connections. By utilising the flaw, which Mr Vanhoef is calling KRACK (for Key Reinstallation Attack), malicious actors could potentially eavesdrop on the traffic of any access point they were physically near.

Companies are currently rolling out updates to computer and mobile operating systems, as well as firmware for routers and other internet devices, that address the problem.

"The attack works against all modern protected Wi-Fi networks," Mr Vanhoef says on a website he created to share information on the flaw. "If your device supports Wi-Fi, it is most likely affected."