Events Manager < 7.2.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'events_list_grouped' Shortcode

Description

The Events Manager – Calendar, Bookings, Tickets, and more! plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'events_list_grouped' shortcode in all versions up to, and including, 7.2.2.1 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.