https://www.bleepingcomputer.com/news/security/z-shave-attack-could-impact-over-100-million-iot-devices/

The Z-Wave wireless communications protocol used for some IoT/smart devices is vulnerable to a downgrade attack that can allow a malicious party to intercept and tamper with traffic between smart devices.

The attack —codenamed Z-Shave— relies on tricking two smart devices that are pairing into thinking one of them does not support the newer S-Wave S2 security features, forcing both to use the older S0 security standard.