A vulnerability has been identified in Siveillance VMS 2017 R2 (All versions < V11.2a), Siveillance VMS 2018 R1 (All versions < V12.1a), Siveillance VMS 2018 R2 (All versions < V12.2a), Siveillance VMS 2018 R3 (All versions < V12.3a), Siveillance VMS 2019 R1 (All versions < V13.1a). An attacker with network access to port 80/TCP could change user roles without proper authorization. The security vulnerability could be exploited by an authenticated attacker with network access to the affected service. No user interaction is required to exploit this security vulnerability. Successful exploitation compromises confidentiality, integrity and availability of the targeted system. At the time of advisory publication no public exploitation of this security vulnerability was known.