cosenary Instagram-PHP-API (aka Instagram PHP API V2), used in the UserPro plugin through 4.9.32 for WordPress, is vulnerable to cross-site scripting via the [example/success.php](https://github.com/cosenary/Instagram-PHP-API/blob/master/example/success.php#L36 ) error_description parameter. Vulnerable code: ```php if (isset($_GET['error'])) { echo 'An error occurred: ' . $_GET['error_description']; } ``` Proof-of-Concept: `https://domain.tld/wp-content/plugins/userpro/lib/instagram/vendor/cosenary/instagram/example/success.php?error=&error_description=<PAYLOAD>`