Appointment Booking Calendar <= 1.4.4 - Authenticated (Author+) Stored Cross-Site Scripting via Custom Booking Field Label

The Appointment Booking Calendar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via custom booking field labels in all versions up to, and including, 1.4.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.