The Webling plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 3.9.0 due to insufficient input sanitization, insufficient output escaping, and missing capabilities checks in the 'webling_admin_save_form' and 'webling_admin_save_memberlist' functions. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject Webling forms and memberlists with arbitrary web scripts that will execute whenever an administrator views the related form or memberlist area of the WordPress admin.