The Advanced Classifieds & Directory Pro plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'phone' parameter in all versions up to, and including, 3.4.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with custom-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This vulnerability is only exploitable on sites where the 'Force Bootstrap' miscellaneous setting (acadp_misc_settings['force_bootstrap']) is enabled and the 'ACADP Listing Address' widget is placed on a sidebar displayed on single listing pages; both conditions are non-default.