The Email Encoder WordPress plugin before 2.3.4 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 unfiltered_html capability is disallowed (for example in multisite setup).
The Email Encoder WordPress plugin before 2.2.2 does not escape the WP_Email_Encoder_Bundle_options[protection_text] parameter before outputting it back in an attribute in an admin page, leading to a Stored Cross-Site Scripting
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Jannis Thuemmig Email Encoder plugin <= 2.1.8 versions.