The Event Espresso 4 Decaf plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 4.10.11. This is due to missing or incorrect nonce validation on the ajaxHandler() function. This makes it possible for unauthenticated attackers to op into notifications via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

A cross-site scripting (XSS) vulnerability in wp-content/plugins/event-espresso-core-reg/admin_pages/messages/templates/ee_msg_admin_overview.template.php in the Event Espresso Core plugin before 4.10.7.p for WordPress allows remote attackers to inject arbitrary web script or HTML via the page parameter.

SQL Injection exists in /includes/event-management/index.php in the event-espresso-free (aka Event Espresso Lite) plugin v3.1.37.12.L for WordPress via the recurrence_id parameter to /wp-admin/admin.php.

Vulnerability in wordpress plugin Event Expresso Free v3.1.37.11.L, The function edit_event_category does not sanitize user-supplied input via the $id parameter before passing it into an SQL statement.