MusicCenter / Trivum Multiroom Setup Tool V8.76 - SNR 8604.26 - C4 Professional before V9.34 build 13381 - 12.07.18, allow unauthorized remote attackers to reset the authentication via the "/xml/system/setAttribute.xml" URL, using the GET request "?id=0&attr=protectAccess&newValue=0" (a successful attack will allow attackers to login without authorization).