CVE-2026-39756 in Wappointment Plugin
Summary
by MITRE • 10/06/2026
Unauthenticated Insecure Direct Object References (IDOR) in Wappointment <= 2.7.7 versions.
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Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified as an Unauthenticated Insecure Direct Object Reference within the Wappointment plugin, specifically affecting versions up to and including 2.7.7, represents a critical failure in access control mechanisms that allows attackers to manipulate object identifiers directly without proper authorization checks. This type of flaw is fundamentally rooted in CWE-639, which describes situations where an application exposes internal implementation objects such as files or database records through user-supplied input data like URL parameters or form fields. In the context of Wappointment, this likely manifests when the plugin processes requests related to appointment management, customer data retrieval, or administrative settings by accepting direct references to these resources from external sources without verifying that the requesting entity has legitimate permission to access them. The absence of authentication requirements exacerbates the severity, as it removes the primary barrier preventing unauthorized entities from interacting with sensitive backend systems.
From a technical perspective, this vulnerability allows any remote actor on the internet to enumerate and potentially modify or delete data belonging to other users or administrators by simply altering specific parameters in HTTP requests directed at the plugin's endpoints. For instance, an attacker might change a user ID or appointment ID parameter from one value to another within a request string, thereby gaining access to private information such as client contact details, scheduled times, payment records, or internal notes that were intended for different users. Because the flaw is unauthenticated, there is no need for credential theft or session hijacking; the attack can be executed anonymously using standard web tools or automated scripts. This significantly lowers the barrier to entry for malicious actors and increases the likelihood of exploitation in the wild, particularly against websites running outdated versions of this widely used WordPress plugin that handle sensitive customer scheduling data.
The operational impact of this vulnerability is substantial, encompassing both confidentiality breaches and potential integrity violations depending on the specific functions exposed through the insecure endpoints. Confidentiality impacts include the unauthorized disclosure of personally identifiable information (PII), which can lead to privacy violations under regulations such as GDPR or CCPA if customer names, phone numbers, emails, or appointment histories are leaked. Integrity risks arise if the vulnerability allows for the modification or deletion of appointments and user profiles, potentially causing business disruption by canceling scheduled services or corrupting administrative records. Furthermore, in some implementations of IDOR vulnerabilities within WordPress plugins, these flaws can serve as a stepping stone for more severe attacks such as Cross-Site Scripting (XSS) if reflected input is not properly sanitized before being rendered back to the browser, although the primary classification here remains focused on access control failures.
In terms of threat modeling and industry frameworks, this vulnerability aligns closely with MITRE ATT&CK technique T1078, specifically Valid Accounts or Default Accounts in some contexts where default permissions are overly permissive, but more accurately fits under general unauthorized access patterns often associated with reconnaissance and data exfiltration phases. It also relates to CWE-269 regarding Improper Privilege Management, as the system fails to enforce appropriate privileges for different user roles. The lack of authentication requirement places it in a high-risk category similar to CVEs involving broken object level authorization (BOLA), which has been consistently ranked among the top security risks by OWASP over recent years due to its prevalence and ease of exploitation in modern web applications that rely heavily on RESTful APIs or AJAX-driven interfaces common in WordPress plugins.
To mitigate this vulnerability, immediate action is required from site administrators and developers maintaining instances of Wappointment version 2.7.7 or lower. The most effective remediation strategy is to upgrade the plugin to a patched version where the vendor has implemented proper authorization checks ensuring that users can only access resources they own or are explicitly permitted to view. Developers should enforce strict server-side validation for all object identifiers, implementing role-based access control (RBAC) logic before processing any request related to appointment data. Additionally, input sanitization and output encoding should be applied rigorously to prevent secondary vulnerabilities like XSS that might arise from the same endpoints. For organizations unable to upgrade immediately due to compatibility constraints, applying a Web Application Firewall rule to block suspicious patterns of parameter manipulation or restricting access to affected plugin files via server configuration can provide temporary protection until a permanent fix is deployed. Regular security audits and penetration testing are recommended to identify similar IDOR flaws in other components of the web application stack.