Simple post listing <= 0.2 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode

The Simple post listing plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'class_name' parameter in the postlist shortcode in all versions up to, and including, 0.2. This is due to insufficient input sanitization and output escaping on user-supplied attributes. 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 via mouse interaction.