Description
WordPress Plugin Registration Forms-User Registration Forms, Invitation-Based Registrations, Front-end User Profile, Login Form & Content Restriction is prone to an open redirect vulnerability because the application fails to properly verify user-supplied input. Exploiting this issue may allow attackers to redirect users to arbitrary web sites and conduct phishing attacks; other attacks are also possible. WordPress Plugin Registration Forms-User Registration Forms, Invitation-Based Registrations, Front-end User Profile, Login Form & Content Restriction version 3.8.2.2 is vulnerable; prior versions may also be affected.
Remediation
Update to plugin version 3.8.2.3 or latest
References
https://wpscan.com/vulnerability/832c6155-a413-4641-849c-b98ba55e8551
https://plugins.svn.wordpress.org/pie-register/trunk/readme.txt