EmbedPress <= 3.8.2 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode

The EmbedPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'embedpress_calendar' shortcode in versions up to, and including, 3.8.2 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.