Input validation vulnerability in Product Visibility by Country for WooCommerce 1.4.9

The Product Visibility by Country for WooCommerce plugin for WordPress has a security flaw that allows attackers with administrator-level permissions to inject malicious scripts into webpages. This vulnerability affects all versions up to and including 1.4.9, and only affects multi-site installations and installations where unfiltered_html has been disabled. This happens because the plugin does not properly sanitize data input or properly escape data output.