Amid the security review of AffiliateWP plugin for WordPress CMS, Security Vulnerabilities was found utilizing DefenseCode ThunderScan by Neven Biruski in application source code security testing phase.
XSS is a very commonly exploited vulnerability type which is very widely spread and easily detectable.
In the event that the administrator of the site makes a request to such a URL, the attacker’s code will be executed, with unlimited access to the WordPress site being referred to. The attacker can attract the administrator to visit the URL in different ways, including sending the URL by email, posting it as a piece of the comment on the vulnerable site or another way.
As per the plugin creators, AffiliateWP is a simple to-utilize, solid WordPress module that gives you the affiliate marketing tools that used to develop your business and profit. In 2016 it outperformed $500,000 in yearly income.
The bug has been reported to Vendor by Defense code and they released a fix on 2017/05/17. So the solution is simple, you need to update to the latest available version of AffiliateWP plugin.