WPBakery Visual Composer <= 7.5 - Authenticated (Contributor+) Stored Cross-Site Scripting via Custom Heading tag attribute

The wpbakery plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Custom Heading tag attribute in all versions up to, and including, 7.5 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor access or higher, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.