Maintenance Redirect < 2.1.0 - IP Spoofing to Maintenance Mode Bypass

Description

The Maintenance Redirect plugin for WordPress is vulnerable to IP Address Spoofing in all versions up to, and including, 2.0.1 due to insufficient IP address validation and use of user-supplied HTTP headers as a primary method for IP retrieval. This makes it possible for unauthenticated attackers to spoof their IP address and bypass maintenance mode.