An issue was discovered on GL.iNet devices through 4.5.0. Attackers can invoke the add_user interface in the system module to gain root privileges. This affects A1300 4.4.6, AX1800 4.4.6, AXT1800 4.4.6, MT3000 4.4.6, MT2500 4.4.6, MT6000 4.5.0, MT1300 4.3.7, MT300N-V2 4.3.7, AR750S 4.3.7, AR750 4.3.7, AR300M 4.3.7, and B1300 4.3.7.
https://github.com/gl-inet/CVE-issues/blob/main/4.0.0/Add_user_vulnerability.md