Regarding CVE-2021-31251, it has been reported that the CHIYU serial converters and SEMAC door control panels are affected by a security vulnerability.
Because the telnet is able to connect with the device.

For this reason, CHIYU would like to include below the measures to fix the problem.

Starting from now, all shipments of the affected devices will come equipped with the latest firmware version which addresses the security vulnerability. The updated firmware will disable the telnet function on the devices.

if you want to upgrade your converter's firmware, please contact CHIYU for upgrading. Contact:

I agree