The Simple Banner WordPress plugin before 3.3.3 does not correctly limit the capabilities it grants to the user roles an administrator allows to manage its banners, granting such roles the full administrator capability, which allows users in a low-privileged role to escalate their privileges and fully compromise the site.

The Simple Banner – Easily add multiple Banners/Bars/Notifications/Announcements to the top or bottom of your website plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'proversionactivationcode' parameter in all versions up to, and including, 3.0.10 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfilteredhtml has been disabled.

The Simple Banner – Easily add multiple Banners/Bars/Notifications/Announcements to the top or bottom of your website plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 3.0.5 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfilteredhtml has been disabled.

The Simple Banner WordPress plugin before 3.0.4 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfilteredhtml capability is disallowed (for example in multisite setup).