CVE-2026-1704 in Appointment Booking Calendar Plugin
Summary
by MITRE • 03/13/2026
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.9.29. This is due to the `get_item_permissions_check` method granting access to users with the `ssa_manage_appointments` capability without validating staff ownership of the requested appointment. This makes it possible for authenticated attackers, with custom-level access and above (users granted the ssa_manage_appointments capability, such as Team Members), to view appointment records belonging to other staff members and access sensitive customer personally identifiable information via the appointment ID parameter.
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Analysis
by VulDB Data Team • 03/20/2026
The vulnerability identified as CVE-2026-1704 affects the Appointment Booking Calendar plugin for WordPress, specifically targeting versions up to and including 1.6.9.29. This represents a critical security flaw that undermines the integrity of appointment management systems within the WordPress ecosystem. The plugin serves as a scheduling solution for businesses and service providers, making it a potentially attractive target for malicious actors seeking unauthorized access to sensitive customer data. The vulnerability manifests through an insecure direct object reference issue that allows unauthorized data access through manipulated appointment identifiers.
The technical flaw resides within the `get_item_permissions_check` method which fails to properly validate staff ownership when processing appointment requests. This method grants access to any user possessing the `ssa_manage_appointments` capability without implementing proper ownership verification mechanisms. The absence of staff ownership validation creates a direct path for authenticated attackers to manipulate the appointment ID parameter and gain access to appointment records belonging to other staff members. This flaw directly maps to CWE-284, which describes insecure direct object references where applications fail to verify that the user has proper authorization to access specific objects.
The operational impact of this vulnerability extends beyond simple data exposure, as it enables attackers to access sensitive personally identifiable information belonging to customers. Team members and other users with the `ssa_manage_appointments` capability can exploit this weakness to view confidential appointment details, customer contact information, appointment times, and potentially other personal data. The attack vector requires only authenticated access with the specified capability, making it particularly dangerous in environments where multiple staff members share administrative privileges. This vulnerability undermines the principle of least privilege and creates opportunities for data breaches that could result in privacy violations and regulatory compliance issues.
Organizations using this plugin face significant security risks including potential data leakage, unauthorized access to customer records, and possible violations of data protection regulations such as gdpr or ccpa. The vulnerability affects the core functionality of appointment management systems, potentially compromising business operations and customer trust. Attackers can systematically enumerate appointment IDs to access multiple records, creating a comprehensive view of scheduling patterns and customer data across different staff members. This type of vulnerability is particularly concerning in the context of the attack chain described in the attack technique matrix, where initial access through legitimate capabilities can be escalated to broader data access and exfiltration.
Mitigation strategies should focus on immediate plugin updates to versions that address the insecure direct object reference issue, proper capability assignment to limit access based on staff ownership, and implementation of additional access controls. Organizations should conduct thorough audits of user capabilities and ensure that staff members only have access to appointment data relevant to their specific responsibilities. The recommended solution involves implementing proper object ownership validation within the `get_item_permissions_check` method to verify that users can only access appointment records they have legitimate authorization to view. Regular security assessments of WordPress plugins and adherence to security best practices including principle of least privilege and proper access control mechanisms are essential for preventing similar vulnerabilities from occurring in the future.