CVE-2026-40789: Amelia Information Disclosure Flaw

CVE-2026-40789 Overview

CVE-2026-40789 is an unauthenticated sensitive data exposure vulnerability in the Amelia booking plugin for WordPress, affecting versions up to and including 2.2. The flaw allows remote attackers to access confidential information without authentication, classified under [CWE-201] Insertion of Sensitive Information Into Sent Data. The vulnerability impacts confidentiality but does not affect integrity or availability of the underlying system. Patchstack published the advisory on June 15, 2026.

Critical Impact
Unauthenticated attackers can retrieve sensitive booking data, including customer information, over the network without user interaction.

Affected Products

Amelia Booking plugin for WordPress, versions <= 2.2
WordPress sites running the ameliabooking plugin
Any deployment exposing the plugin's endpoints to untrusted networks

Discovery Timeline

2026-06-15 - CVE-2026-40789 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-40789

Vulnerability Analysis

The Amelia plugin provides appointment and event booking functionality for WordPress sites. In versions up to 2.2, one or more endpoints return sensitive information without enforcing authentication or authorization checks. An unauthenticated remote attacker can issue HTTP requests to retrieve data that should be restricted to administrators or booking owners.

The weakness corresponds to [CWE-201], where sensitive data is included in responses sent to clients that should not have access. Exposed data in booking platforms typically includes customer names, email addresses, phone numbers, appointment details, and internal configuration values. The vulnerability is network-reachable and requires no privileges or user interaction.

Root Cause

The root cause is missing access control on data-returning endpoints in the ameliabooking plugin. Request handlers serialize and return records without verifying that the requester is authorized to view them. Refer to the Patchstack Vulnerability Report for advisory details.

Attack Vector

Exploitation occurs over the network against the public WordPress site hosting the vulnerable plugin. An attacker sends crafted HTTP requests to the affected plugin endpoint and parses the response to extract sensitive booking records. No authentication, special tooling, or social engineering is required, which makes mass-scanning and automated harvesting straightforward.

Detection Methods for CVE-2026-40789

Indicators of Compromise

Unauthenticated HTTP requests to /wp-admin/admin-ajax.php or REST routes referencing amelia or ameliabooking from unfamiliar IP addresses
Spikes in outbound response sizes from plugin endpoints, indicating bulk data retrieval
Repeated sequential or enumeration-style requests against booking-related parameters

Detection Strategies

Inspect web server access logs for unauthenticated requests to Amelia plugin endpoints returning HTTP 200 with large payloads
Deploy WAF rules to flag requests to ameliabooking actions originating from unauthenticated sessions
Correlate user-agent patterns and request rates to identify automated scrapers targeting the plugin

Monitoring Recommendations

Enable verbose logging on the WordPress site, including REST API and AJAX handlers
Forward web and application logs to a centralized SIEM for retention and query
Alert on anomalous data egress volumes from the WordPress host

How to Mitigate CVE-2026-40789

Immediate Actions Required

Update the Amelia plugin to a version newer than 2.2 as soon as the vendor patch is available
Audit booking records to determine what data may have been accessed by unauthenticated requests
Notify affected customers if personally identifiable information was exposed, in line with applicable regulations

Patch Information

Consult the Patchstack Vulnerability Report for the fixed version and upgrade guidance. Apply the vendor-supplied update through the WordPress plugin manager or by replacing the plugin files manually.

Workarounds

Restrict access to Amelia plugin endpoints using a Web Application Firewall until patching is complete
Limit plugin functionality to authenticated sessions through server-level access controls
Temporarily disable the ameliabooking plugin on sites that cannot be patched immediately

bash

# Example: block unauthenticated access to Amelia endpoints at the web server
# nginx snippet
location ~* /wp-admin/admin-ajax.php {
    if ($arg_action ~* "^wpamelia") {
        return 403;
    }
}