What the vulnerability does
01Description
The Booking for Appointments and Events Calendar – Amelia plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 2.1.3. This is due to the `UpdateProviderCommandHandler` failing to validate changes to the `externalId` field when a Provider (Employee) user updates their own profile. The `externalId` maps directly to a WordPress user ID and is passed to `wp_set_password()` and `wp_update_user()` without authorization checks. This makes it possible for authenticated attackers, with Provider-level (Employee) access and above, to take over any WordPress account — including Administrator — by injecting an arbitrary `externalId` value when updating their own provider profile.
Explanation of Vulnerability in Simple Terms
02Summary
Amelia Booking for Appointments and Events Calendar versions 2.1.3 and earlier contain an authorization flaw that allows authenticated users with low privileges to read, modify, or delete sensitive data and disrupt service. The vulnerability requires a valid user account but no special interaction. All installations running affected versions should update immediately.
What an attacker can do
03Attacker Capabilities
Read, modify, or delete sensitive data; disrupt the booking service.
Potential impact on your site
04Site Impact
Authenticated users can access and alter appointment data, customer information, and calendar settings without proper authorization.
Conditions required to exploit
05Prerequisites
Valid user account with low privileges; network access to the site.
Key dates
06Disclosure timeline
April 7, 2026
CVE published
April 8, 2026
Record updated
