A security protocol at the heart of most modern Wi-Fi devices, including computers, phones, and routers, has been broken, putting almost every wireless-enabled device at risk of attack. From a report: The bug, known as "KRACK" for Key Reinstallation Attack, exposes a fundamental flaw in WPA2, a common protocol used in securing most modern wireless networks. Mathy Vanhoef, a computer security academic, who found the flaw, said the weakness lies in the protocol's four-way handshake, which securely allows new devices with a pre-shared password to join the network. That weakness can, at its worst, allow an attacker to decrypt network traffic from a WPA2-enabled device, hijack connections, and inject content into the traffic stream. In other words: hackers can eavesdrop on your network traffic. The bug represents a complete breakdown of the WPA2 protocol, for both personal and enterprise devices -- putting every supported device at risk. "If your device supports Wi-Fi, it is most likely affected," said Vanhoef, on his website. News of the vulnerability was later confirmed on Monday by US Homeland Security's cyber-emergency unit US-CERT, which about two months ago had confidentially warned vendors and experts of the bug, ZDNet has learned.