An issue was discovered in NJHYST HY511 POE core before 2.1 and plugins before 0.1. The vulnerability stems from the device's insufficient cookie verification, allowing an attacker to directly request the configuration file address and download the core configuration file without logging into the device management backend. By reading the corresponding username and self-decrypted MD5 password in the core configuration file, the attacker can directly log in to the backend, thereby bypassing the front-end backend login page.