This indicates an attack attempt to exploit a Security Bypass vulnerability in Serviio Media Server.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application when handling a crafted request. A remote attacker can exploit this to change the password for arbitrary accounts.
Serviio Media Server PRO 188.8.131.52
Serviio Media Server 1.6.1
Serviio Media Server 1.7.0
Serviio Media Server 1.7.1
Security Bypass: Remote attackers can bypass security features of vulnerable systems.
Currently we are unaware of any vendor supplied patch for this issue