An issue was discovered on FiberHome Fengine S5800 switches V210R240. An unauthorized attacker can access the device's SSH service, using a password cracking tool to establish SSH connections quickly. This will trigger an increase in the SSH login timeout (each of the login attempts will occupy a connection slot for a longer time). Once this occurs, legitimate login attempts via SSH/telnet will be refused, resulting in a denial of service; you must restart the device.