The WP AdCenter – Ad Manager & Adsense Ads plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘ad_alignment’ attribute in all versions up to, and including, 2.5.6 due to insufficient input sanitization and output escaping. 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.
https://wordpress.org/plugins/wpadcenter/#developers
https://plugins.trac.wordpress.org/changeset/3146736/#file6
https://plugins.trac.wordpress.org/changeset/3146736/
https://plugins.trac.wordpress.org/browser/wpadcenter/trunk/admin/class-wpadcenter-admin.php#L3127
https://plugins.trac.wordpress.org/browser/wpadcenter/trunk/admin/class-wpadcenter-admin.php#L3020
https://plugins.trac.wordpress.org/browser/wpadcenter/trunk/admin/class-wpadcenter-admin.php#L2922