Security researcher: Most WiFi networks that use WPA2 appear to be vulnerable. Key reinstallation attacks can be used to replace an in-use key with an attacker-created one. Successful exploits allow an attacker to gain man-in-the-middle access to communications and potentially inject malicious data. The U.S. Computer Emergency Response Team has issued a Sunday alert about the threat of key reinstallations attacks against Wi-Fi Protected Access II (WPA2) networks.”]
Source: https://www.databreachtoday.com/wifi-security-shredded-via-krack-attack-a-10381