Waveshare RS232/485 TO WIFI ETH (B) Serial to Ethernet/Wi-Fi Gateway Firmware V3.1.1.0: HW 4.3.2.1: Webpage V7.04T.07.002880.0301 allows attackers to set the Administrator password and username as blank values, allowing attackers to bypass authentication.
https://otsecverse.github.io/OTSecVerse/posts/Post-2/
https://drive.google.com/file/d/1AGv9KWMTB71NJfIOncuNO6FyK0UAqxmL/view?usp=sharing