A Really Simple Chat Multiple SQL Injection Vulnerabilities

The host is running A Really Simple Chat and is prone to multiple SQL injection vulnerabilities.
Successful exploitation will allow attacker to alter queries to the SQL database, execute arbitrary queries to the database, compromise the application, access or modify sensitive data. Impact Level: Application
No solution or patch was made available for at least one year since disclosure of this vulnerability. Likely none will be provided anymore. General solution options are to upgrade to a newer release, disable respective features, remove the product or replace the product by another one.
The flaws are due to improper validation of user supplied data to 'arsc_user parameter' in edit_user.php, 'arsc_layout_id' parameter in edit_layout.php and 'arsc_room' parameter in edit_room.php, which allows attacker to execute arbitrary SQL commands.
A Really Simple Chat version 3.3-rc2.