The exploit, as first reported by Ars Technica, takes advantage of several key management vulnerabilities in the WPA2 security protocol, the popular authentication scheme used to protect personal and enterprise Wi-Fi networks. "If your device supports Wi-Fi, it is most likely affected," say researchers.
So yeah, this is bad.
The United States Computer Emergency Readiness Team issued the following warning in response to the exploit:
US-CERT has become aware of several key management vulnerabilities in the 4-way handshake of the Wi-Fi Protected Access II (WPA2) security protocol. The impact of exploiting these vulnerabilities includes decryption, packet replay, TCP connection hijacking, HTTP content injection, and others. Note that as protocol-level issues, most or all correct implementations of the standard will be affected. The CERT/CC and the reporting researcher KU Leuven, will be publicly disclosing these vulnerabilities on 16 October 2017.