CVE-2026-18441 in Appointment Booking Plugin
Summary
by MITRE • 09/18/2026
The Appointment Booking Plugin – LatePoint | Calendar & Scheduling for WordPress plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 5.6.9 via the set_customer_object due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to enumerate arbitrary customer records and disclose personally identifiable information - including first name, last name, email address, and phone number - by iterating the customer[id] parameter. This issue is exploitable only when the site is configured with customer authentication disabled (guest checkout enabled).
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Analysis
by VulDB Data Team • 09/18/2026
The vulnerability identified in the Appointment Booking Plugin LatePoint for WordPress affects all versions up to 5.6.9 and represents a classic instance of an Insecure Direct Object Reference, commonly categorized under CWE-284 within industry standard classification systems. This flaw arises from insufficient validation mechanisms applied to user-controlled input parameters, specifically the customer identifier passed through the set_customer_object endpoint. When attackers manipulate this parameter by iterating through sequential or predictable integer values, they can bypass access controls and retrieve data associated with arbitrary customer records stored in the application database. The core technical failure lies in the absence of proper authorization checks that would verify whether the requesting user has legitimate permission to view the specific resource being accessed.
The operational impact of this vulnerability is significant due to the sensitive nature of the information exposed. Successful exploitation allows unauthenticated attackers to enumerate customer records and disclose personally identifiable information, including first names, last names, email addresses, and phone numbers. This data leakage poses serious privacy risks for both end-users and businesses relying on the plugin for appointment scheduling. The exposure of such details can facilitate further malicious activities such as phishing campaigns, social engineering attacks, or identity theft against affected individuals. Furthermore, the ability to systematically scrape this information undermines trust in the platform and may lead to regulatory compliance issues under data protection laws like GDPR or CCPA if customer data is mishandled due to these security gaps.
It is crucial to note that exploitation of this vulnerability is conditional upon specific site configurations. The attack vector remains viable only when the WordPress site has guest checkout enabled, meaning customer authentication is disabled for appointments. In environments where strict user authentication and session management are enforced, the impact might be mitigated as attackers would need valid credentials to interact with certain parts of the system. However, many businesses prefer guest checkouts for convenience and ease of use, inadvertently leaving them exposed to this type of enumeration attack. This highlights a common trade-off between usability and security in web application design where disabling authentication features can introduce severe vulnerabilities if not accompanied by robust input validation and access control measures.
To mitigate the risks associated with CWE-284 Insecure Direct Object Reference, developers must implement strict authorization checks on all endpoints that handle sensitive data retrieval. This includes validating that the requesting user has explicit permission to access the specific resource identified by the object reference parameter. Additionally, implementing rate limiting and monitoring for unusual patterns of requests can help detect automated enumeration attempts in real-time. From a defense-in-depth perspective, organizations should consider disabling guest checkout if possible or ensuring that any public-facing endpoints are thoroughly tested using static analysis tools and dynamic vulnerability scanners to identify similar flaws before deployment. Regular security audits focusing on access control logic are essential to maintain the integrity of customer data within WordPress ecosystems utilizing third-party plugins like LatePoint.