In totolink a3100r V5.9c.4577, the hard-coded telnet password can be discovered from official released firmware. An attacker, who has connected to the Wi-Fi, can easily telnet into the target with root shell if the telnet is function turned on.

Totolink A3100R V5.9c.4577 suffers from Use of Insufficiently Random Values via the web configuration. The SESSIONID is predictable. An attacker can hijack a valid session and conduct further malicious operations.