CVE-2026-2931: Amelia Booking Auth Bypass Vulnerability

CVE-2026-2931 Overview

The Amelia Booking plugin for WordPress contains an Insecure Direct Object Reference (IDOR) vulnerability in versions up to and including 9.1.2. This security flaw stems from the plugin providing user-controlled access to objects without proper authorization checks, allowing attackers to bypass intended access restrictions and manipulate system resources. Authenticated attackers with customer-level permissions or higher can exploit this vulnerability to change user passwords, potentially leading to full administrator account takeover.

Critical Impact

Authenticated attackers with minimal privileges can escalate to administrator access by changing passwords of any user account, including administrators, leading to complete site compromise.

Affected Products

• Amelia Booking Plugin for WordPress versions up to and including 9.1.2
• Amelia Booking Pro Plugin (shares the same slug)
• WordPress installations running vulnerable Amelia Booking versions

Discovery Timeline

• 2026-03-26 - CVE CVE-2026-2931 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-2931

Vulnerability Analysis

This Insecure Direct Object Reference vulnerability exists within the Amelia Booking plugin's user management functionality. The core issue lies in the UpdateCustomerCommandHandler.php and UpdateCustomerController.php files, where user update operations lack sufficient authorization validation. When a customer account submits a request to update user details, the application fails to verify that the requesting user has appropriate permissions to modify the target account.

The vulnerability enables horizontal and vertical privilege escalation scenarios. An attacker authenticated as a low-privileged customer can manipulate object references in update requests to target administrator accounts. Since password change operations are processed without verifying ownership or proper authorization hierarchy, attackers can reset any user's password and subsequently gain unauthorized access to those accounts.

Root Cause

The root cause is classified under CWE-269 (Improper Privilege Management). The plugin's architecture allows direct object manipulation without implementing proper access control checks. Specifically, the user update endpoint accepts user identifiers that can be modified by the attacker, and the backend processing logic trusts these client-supplied values without validating that the authenticated user has authority over the target resource. This represents a fundamental authorization bypass where the application relies on obscurity rather than proper access control mechanisms.

Attack Vector

The attack is network-based and requires low-privileged authenticated access. An attacker first creates or gains access to a customer account on a WordPress site running the vulnerable Amelia Booking plugin. Using authenticated API requests to the user update functionality, the attacker modifies the target user ID parameter to reference an administrator account. By submitting a password change request with the manipulated reference, the attacker can set a new password for the administrator account. Once the administrator password is changed, the attacker can log in with full administrative privileges.

The vulnerability is exploited through manipulation of the customer update API endpoints. The UpdateCustomerController.php at line 30 processes update requests and passes them to UpdateCustomerCommandHandler.php, which at line 173 handles the actual user modification without adequate authorization verification. Technical details are available in the WordPress Plugin Code Reference and Update Controller Reference.

Detection Methods for CVE-2026-2931

Indicators of Compromise

• Unexpected password reset activity for administrator or privileged user accounts
• API requests to customer update endpoints containing user IDs that don't match the authenticated session
• Multiple failed login attempts followed by successful authentication for administrator accounts
• Unusual activity patterns from customer-level accounts accessing administrative functions

Detection Strategies

• Monitor WordPress API logs for anomalous requests to Amelia Booking user update endpoints
• Implement alerting on password changes for privileged accounts, especially when initiated through plugin APIs
• Review access logs for customer accounts making requests with mismatched user ID parameters
• Deploy web application firewall rules to detect IDOR attack patterns in request parameters

Monitoring Recommendations

• Enable detailed logging for the Amelia Booking plugin's user management functions
• Configure SIEM alerts for privilege escalation indicators such as customer-to-admin role changes
• Monitor for bulk or rapid password change requests through the plugin's API endpoints
• Establish baseline behavior for legitimate user update operations to identify anomalies

How to Mitigate CVE-2026-2931

Immediate Actions Required

• Update the Amelia Booking plugin to a patched version newer than 9.1.2 immediately
• Audit all administrator and privileged user accounts for unauthorized password changes
• Review recent login activity for signs of account compromise
• Force password resets for all administrator accounts as a precautionary measure
• Temporarily disable the Amelia Booking plugin if an update is not immediately available

Patch Information

Site administrators should update the Amelia Booking plugin through the WordPress admin panel or by downloading the latest version from the vendor. The vulnerability affects both the free and pro versions of the plugin (which share the same slug). For additional information about the plugin, refer to the Codecanyon Plugin Overview. Detailed vulnerability analysis is available from Wordfence.

Workarounds

• Restrict access to customer registration and account management features until patched
• Implement additional web application firewall rules to validate user ID parameters in API requests
• Enable multi-factor authentication for all administrator accounts to mitigate password-based attacks
• Consider implementing IP-based access restrictions for WordPress administrative functions

# WordPress CLI command to check Amelia Booking plugin version
wp plugin list --name=ameliabooking --format=table

# Update plugin to latest version via CLI
wp plugin update ameliabooking

# Temporarily deactivate plugin if patching is not immediately possible
wp plugin deactivate ameliabooking