The Mang Board WP plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the board_header and board_footer parameters in all versions up to, and including, 1.8.6 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.
https://plugins.trac.wordpress.org/changeset/3272163/mangboard/trunk