wpForo Forum <= 2.1.7 - Authenticated (Subscriber+) Local File Include, Server-Side Request Forgery, and PHAR Deserialization via file_get_contents

The wpForo Forum plugin for WordPress is vulnerable to Local File Include, Server-Side Request Forgery, and PHAR Deserialization in versions up to, and including, 2.1.7. This is due to the insecure use of file_get_contents without appropriate verification of the data being supplied to the function. This makes it possible for authenticated attackers, with minimal permissions such as a subscriber, to retrieve the contents of files like wp-config.php hosted on the system, perform a deserialization attack and possibly achieve remote code execution, and make requests to internal services.