WordPress Plugin Relevanssi - 'category_name' SQL Injection

source: https://www.securityfocus.com/bid/65960/info

Relevanssi plugin for WordPress is prone to an SQL-injection vulnerability because the application fails to properly sanitize user-supplied input before using it in an SQL query.

A successful exploit could allow an attacker to compromise the application, access or modify data, or exploit vulnerabilities in the underlying database.

Versions prior to Relevanssi 3.3 are vulnerable. 

http://www.example.com/wordpress/wp-content/plugins/wp-realty/index_ext.php?action=contact_friend&popup=yes&listing_id=[SQLi