Fatal Error Notify < 1.5.3 - Subscriber+ Test Error Email Sending

Description The plugin does not have authorisation and CSRF checks in its test_error AJAX action, allowing any authenticated users, such as subscriber to call it and spam the admin email address with error messages. The issue is also exploitable via CSRF

PoC

As a subscriber, open https://example.com/wp-admin/admin-ajax.php?action=test_error The attack can also be performed via CSRF by making a logged in user open the link above