AzuraCast through 0.23.8 Config Injection via frontend_config.custom_config

AzuraCast through 0.23.8 fails to remove frontend_config.custom_config in PUT /station/{id}/profile/edit for users lacking the Manage station broadcasting permission, and the stored JSON is written verbatim as key=value lines into the Shoutcast sc_serv.conf file. An authenticated user with only the Manage station profile permission can override adminpassword, password, and portbase, or inject arbitrary directives via newlines in keys, hijacking the station's Shoutcast frontend.