CVE-2026-105257 in Appointment Booking Plugin
Summary
by MITRE • 10/21/2026
The Appointment Booking Plugin WordPress plugin before 5.7.5 does not verify that an authenticated agent-level user is assigned to a customer before returning or searching that customer's record, allowing any agent to read and enumerate the personal information of every customer on the site, including those managed by other agents.
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Analysis
by VulDB Data Team • 10/21/2026
The vulnerability identified in the Appointment Booking Plugin for WordPress prior to version 5.7.5 represents a critical failure in server-side access control mechanisms, specifically falling under the category of Insecure Direct Object References or Broken Access Control as defined by CWE-639 and mapped to the ATT&CK technique T1078 Valid Accounts. This flaw arises from an insufficient verification process within the plugin's backend logic when handling requests related to customer records. The application architecture assumes that any user authenticated with agent-level privileges has a legitimate business relationship with the target customer record they are attempting to access, but it fails to enforce this assumption through rigorous server-side checks. Consequently, the system does not validate whether the currently logged-in agent is actually assigned to or authorized to view the specific customer data being requested via API endpoints or administrative interfaces.
From a technical perspective, the operational impact of this vulnerability allows for unauthorized information disclosure and user enumeration across the entire WordPress installation. An attacker who has obtained valid credentials for an account with at least agent-level privileges can exploit this logic flaw by manipulating parameters in HTTP requests to target customer IDs belonging to other agents or even administrative users. Since there is no cross-referencing of the requesting user's ID against a designated assignment table, the application returns full personal information profiles for any queried customer record. This includes sensitive personally identifiable information such as names, contact details, and potentially appointment history, which are stored in plaintext or weakly protected formats within the database. The ability to enumerate these records effectively turns the plugin into an information leakage vector that compromises the privacy of all customers registered on the platform, regardless of their assigned service provider.
The security implications extend beyond simple data theft, as this vulnerability facilitates broader reconnaissance and potential account takeover scenarios if combined with other weaknesses such as weak password policies or lack of multi-factor authentication. By systematically iterating through customer IDs, an attacker can build a comprehensive database of victim profiles, which significantly lowers the barrier for subsequent social engineering attacks or targeted phishing campaigns against high-value targets within the organization using the plugin. Furthermore, this exposure violates fundamental principles of data minimization and access control required by regulatory frameworks such as GDPR and CCPA, potentially exposing site administrators to legal liabilities and compliance penalties due to the negligent handling of personal data.
Mitigation strategies must prioritize immediate patching and architectural review. The primary remediation step is to upgrade the Appointment Booking Plugin to version 5.7.5 or later, where this access control logic has been corrected to enforce strict ownership verification before returning any customer data. In environments where upgrading is not immediately feasible, administrators should implement compensating controls such as restricting agent-level user creation to trusted individuals and monitoring logs for unusual patterns of bulk requests that may indicate enumeration attempts. Additionally, implementing Web Application Firewall rules can help detect and block automated scraping activities targeting the affected endpoints until a permanent fix is deployed. Regular security audits focusing on role-based access control implementations are essential to prevent similar vulnerabilities in custom plugins or themes integrated with WordPress core functionalities.