In CMSuno 1.6.2, an attacker can inject malicious PHP code as a "username" while changing his/her username & password. After that, when attacker logs in to the application, attacker's code will be run. As a result of this vulnerability, authenticated user can run command on the server.
CMSUno version 1.6.2 authenticated remote code execution exploit. The original discovery for the vulnerability leveraged is attributed to Fatih Celik in November of 2020.