My Geo Posts Free <= 1.2 - Authenticated (Contributor+) Stored Cross-Site Scripting

The My Geo Posts Free plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'mygeo_city' shortcode in all versions up to, and including, 1.2. This is due to the plugin not properly sanitizing user input or escaping output of the 'default' shortcode attribute. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.