CVE-2026-15250 in Appointment Booking Plugin
Summary
by MITRE • 07/30/2026
The Appointment Booking Plugin WordPress plugin before 5.6.8 does not restrict which booking fields an unauthenticated visitor can set through its public booking funnel, allowing an unauthenticated user to assign a privileged booking field such as the approval status and thereby bypass the site's booking approval workflow.
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Analysis
by VulDB Data Team • 07/30/2026
The Appointment Booking Plugin for WordPress represents a widely used solution for managing scheduling and reservation systems on websites. This particular vulnerability affects versions prior to 5.6.8 and stems from inadequate input validation within the plugin's public booking interface. The flaw manifests as a lack of proper field restriction mechanisms that would normally prevent unauthenticated users from manipulating certain sensitive booking parameters through the frontend booking process.
The technical implementation of this vulnerability involves the plugin's failure to properly sanitize and validate user input submitted through its public booking form. When an unauthenticated visitor submits booking data, the system does not adequately verify which fields can be modified by anonymous users versus those that require authentication or administrative privileges. This oversight allows malicious actors to inject values into privileged fields such as approval status indicators, effectively circumventing the intended workflow controls.
The operational impact of this vulnerability extends beyond simple unauthorized modifications. Attackers can exploit this weakness to approve bookings without proper authorization, potentially leading to service overbooking, unauthorized access to premium services, or disruption of normal business operations. The bypass of the booking approval workflow creates a significant security gap that undermines the entire reservation system's integrity and trust model.
This vulnerability aligns with CWE-20, which addresses improper input validation, and represents a classic example of insufficient access control mechanisms. From an adversarial perspective, this flaw maps to ATT&CK technique T1078 004, representing valid accounts used for unauthorized access, as attackers can manipulate the system through legitimate booking interfaces without requiring elevated privileges. The weakness essentially allows privilege escalation through manipulation of the booking approval status field.
Mitigation strategies should focus on implementing robust input validation and field-level access controls within the plugin's frontend processing logic. Administrators should immediately upgrade to version 5.6.8 or later where this vulnerability has been addressed. Additional protective measures include implementing proper authentication checks for all booking modification operations, logging suspicious booking submissions, and conducting regular security audits of third-party WordPress plugins. Organizations should also consider implementing rate limiting and additional monitoring for unusual booking patterns that might indicate exploitation attempts.
The broader implications highlight the critical importance of validating user inputs and implementing proper access controls in web applications, particularly those handling sensitive business processes like appointment scheduling. This vulnerability demonstrates how seemingly minor oversights in input validation can create significant security risks that affect core business operations and customer trust in digital service platforms.