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
The Email Encoder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'eeb_mailto' shortcode in versions up to, and including, 2.1.8 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. A partial patch was issued in version 2.1.8. The vulnerability was fully patched in 2.1.9.
The Email Encoder – Protect Email Addresses WordPress plugin before 2.1.2 has an endpoint that requires no authentication and will render a user supplied value in the HTML response without escaping or sanitizing the data.