WP Mailster < 1.8.17.0 - Authenticated (Contributor+) Stored Cross-Site Scripting

Description

The WP Mailster plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 1.8.16.0 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.