The function CheckMic() in the Realtek RTL8195A Wi-Fi Module prior to versions released in April 2020 (up to and excluding 2.08) does not validate the size parameter for an internal function, _rt_md5_hmac_veneer() or _rt_hmac_sha1_veneer(), resulting in a stack buffer over-read which can be exploited for denial of service. An attacker can impersonate an Access Point and attack a vulnerable Wi-Fi client, by injecting a crafted packet into the WPA2 handshake. The attacker does not need to know the network's PSK.