The Newsletter Popup WordPress plugin through 1.2 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)
The Newsletter Popup WordPress plugin through 1.2 does not have CSRF check when deleting subscriber, which could allow attackers to make logged in admins perform such action via a CSRF attack
The Newsletter Popup WordPress plugin through 1.2 does not sanitise and escape some parameters, which could allow unauthenticated visitors to perform Cross-Site Scripting attacks against admins
The Newsletter Popup WordPress plugin through 1.2 does not have CSRF checks in some places, which could allow attackers to make logged in users perform unwanted actions via CSRF attacks as the wpnewslettershowlocalrecord page is not protected with a nonce.
The Newsletter Popup WordPress plugin through 1.2 does not sanitise and escape some of its settings, which could allow unauthenticated users to perform Stored Cross-Site Scripting attacks