A denial of service condition exists after an integer overflow in several IoT devices from CHIYU Technology, including BIOSENSE, Webpass, and BF-630, BF-631, and SEMAC. The vulnerability can be explored by sending an unexpected integer (> 32 bits) on the page parameter that will crash the web portal and making it unavailable until a reboot of the device.
https://www.chiyu-tech.com/msg/message-Firmware-update-87.html
https://seguranca-informatica.pt/dancing-in-the-iot-chiyu-devices-vulnerable-to-remote-attacks/
https://gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chiyu-iot-devices#cve-2021-31642
http://packetstormsecurity.com/files/162934/CHIYU-IoT-Denial-Of-Service.html