The WP Maps – Google Maps,OpenStreetMap,Mapbox,Store Locator,Listing,Directory & Filters plugin for WordPress is vulnerable to Stored Cross-Site Scripting via shapes_values Parameter in all versions up to, and including, 4.9.8 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The fc-call-nonce nonce required by the endpoint is exposed to all frontend visitors who view a map page via window.wpgmp_local.nonce, enabling any authenticated subscriber to read the nonce and craft a valid request; additionally, the secondary _wpnonce check in the drawing handler can be bypassed by simply omitting the _wpnonce parameter from the request.