Yokogawa STARDOM FCJ controllers R4.02 and prior, FCN-100 controllers R4.02 and prior, FCN-RTU controllers R4.02 and prior, and FCN-500 controllers R4.02 and prior utilize hard-coded credentials that could allow an attacker to gain unauthorized administrative access to the device, which could result in remote code execution.
https://web-material3.yokogawa.com/1/6712/details/YSAR-18-0004-E.pdf