CVE-2026-8789: Easy Appointments WordPress Plugin Data Modification Vulnerability

The Easy Appointments plugin for WordPress, in versions up to and including 3.12.27, is susceptible to an unauthorized data modification vulnerability, identified as CVE-2026-8789. This critical flaw stems from a missing capability check and lack of nonce verification within the ea_delete_multiple_connections AJAX action. This design oversight enables authenticated attackers, requiring only Contributor-level access or higher on a WordPress site, to arbitrarily delete connection records stored in the wp_ea_connections database table. The successful exploitation of this vulnerability directly disrupts the plugin's core booking functionalities, potentially causing service interruptions and data loss for organizations relying on Easy Appointments for scheduling and client management. The vulnerability could lead to significant operational challenges and impact data integrity.

Attack Chain

1. Attacker gains authenticated access to a WordPress site with at least Contributor-level privileges.
2. The attacker crafts a specific AJAX POST request targeting the /wp-admin/admin-ajax.php endpoint.
3. The request includes the action=ea_delete_multiple_connections parameter and specifies the connection_ids to be deleted.
4. The attacker either omits the _wpnonce parameter or provides an invalid one.
5. Due to the missing capability check, the plugin fails to properly verify the attacker's authorization level for this action.
6. Concurrently, the missing nonce verification allows the request to bypass Cross-Site Request Forgery (CSRF) protection.
7. The plugin's vulnerable ea_delete_multiple_connections function executes, leading to the deletion of specified records from the wp_ea_connections database table.
8. The core booking functionality of the Easy Appointments plugin is disrupted, resulting in data modification and potential service outage.

Impact

The successful exploitation of CVE-2026-8789 allows authenticated attackers to delete critical connection records within the wp_ea_connections database table. This direct data modification disrupts the core booking functionality provided by the Easy Appointments plugin. Organizations using affected versions could face significant operational challenges, including loss of scheduling data, client booking information, and potential service interruptions. While the number of affected organizations is not specified, any entity running the Easy Appointments plugin on WordPress versions up to 3.12.27 is at risk. The vulnerability has a CVSS v3.1 Base Score of 8.1 (High), underscoring its potential for severe impact on data integrity and availability.

Recommendation

• Patch CVE-2026-8789 immediately by updating the Easy Appointments plugin to version 3.12.28 or later.
• Deploy the Sigma rule in this brief to your SIEM and tune for your environment to detect anomalous requests.
• Monitor web server access logs for anomalous or excessive POST requests to /wp-admin/admin-ajax.php with action=ea_delete_multiple_connections originating from unusual user agents or IP addresses, particularly for users with lower privileges.
• Regularly back up your WordPress database, especially the wp_ea_connections table, to facilitate recovery in case of data modification.