Researchers uncovered a new high-severity hardware vulnerability residing in the widely-used Wi-Fi chips manufactured by Broadcom and Cypress. The flaw could let nearby remote remote attackers intercept and decrypt some wireless network packets transmitted over-the-air by a vulnerable device. The attack relies on the fact that when a device suddenly gets disconnected from the wireless network, the chip clears the session key in the memory and set it to zero, but the chip inadvertently transmits all data frames left in the buffer with an all-zero encryption key.
Source: https://thehackernews.com/2020/02/kr00k-wifi-encryption-flaw.html