GEO my WP <= 4.5.5 - Unauthenticated SQL Injection via 'swlatlng' / 'nelatlng' Parameters

Summary

The GEO my WP plugin for WordPress is vulnerable to SQL Injection via the 'swlatlng' and 'nelatlng' parameters in all versions up to, and including, 4.5.5 The parameters are read from $_SERVER['QUERY_STRING'] via parse_str() (bypassing WordPress's wp_magic_quotes protection, which only covers $_POST/$_GET/$_COOKIE/$_REQUEST), then each is split on ',' via explode() and the resulting fragments are interpolated directly into a SQL BETWEEN clause in gmw_get_locations_within_boundaries_sql() without is_numeric() validation, (float) casting, esc_sql(), or $wpdb->prepare(). This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. Exploitation requires the site to host the Posts Locator search-results shortcode (`[gmw form="results" form_id=N]`) on a public page and to have at least one published post with an associated gmw_location row.