An issue was discovered on V-SOL V1600D V2.03.69 and V2.03.57, V1600D4L V1.01.49, V1600D-MINI V1.01.48, V1600G1 V2.0.7 and V1.9.7, and V1600G2 V1.1.4 OLT devices. An low-privileged (non-admin) attacker can use a hardcoded password (4ef9cea10b2362f15ba4558b1d5c081f) to create an admin user.