CVE-2026-1920 in Booktics Plugin
Summary
by MITRE • 03/10/2026
The Booking Calendar for Appointments and Service Businesses – Booktics plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'Extension_Controller::update_item_permissions_check' function in all versions up to, and including, 1.0.16. This makes it possible for unauthenticated attackers to install addon plugins.
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Analysis
by VulDB Data Team • 03/15/2026
The vulnerability identified as CVE-2026-1920 affects the Booktics plugin for WordPress, a booking calendar solution designed for appointment and service businesses. This plugin exposes a critical security flaw through its Extension_Controller::update_item_permissions_check function, which fails to properly validate user capabilities before allowing data modification operations. The absence of proper capability checks creates an unauthorized access vector that allows any attacker to bypass authentication requirements and install malicious addon plugins on vulnerable WordPress installations. This vulnerability exists across all versions of the plugin up to and including version 1.0.16, making it a widespread concern for users who have not updated to newer releases. The flaw directly impacts the integrity of WordPress installations by enabling attackers to deploy unauthorized modifications to the core plugin functionality through the addon installation mechanism.
The technical implementation of this vulnerability stems from a missing capability verification within the plugin's permission control system. The Extension_Controller::update_item_permissions_check function should have validated whether the requesting user possesses the necessary administrative privileges to modify plugin extensions, but this validation is entirely absent. This missing capability check represents a classic example of insufficient authorization control, which aligns with CWE-863, or "Incorrect Authorization." The flaw allows unauthenticated attackers to exploit the plugin's update mechanism by crafting malicious requests that appear to originate from legitimate administrative users. This type of vulnerability is particularly dangerous because it enables attackers to install arbitrary code through the plugin's legitimate update pathways, effectively bypassing standard WordPress security controls that typically prevent unauthorized modifications to core system components.
From an operational perspective, this vulnerability creates significant risk for businesses relying on the Booktics plugin for their appointment scheduling needs. An attacker who successfully exploits this vulnerability can install malicious addon plugins that may include backdoors, data exfiltration tools, or other malicious payloads designed to compromise the entire WordPress installation. The impact extends beyond simple unauthorized modifications to include potential data breaches, service disruption, and the possibility of the compromised system being used as a launching point for further attacks within the network. This vulnerability directly violates the principle of least privilege and can result in complete compromise of the affected WordPress site, especially when combined with other vulnerabilities or when the site hosts sensitive customer information. The attack surface is particularly concerning because the plugin is designed for business use cases where sensitive appointment data and customer information are typically stored.
The mitigation strategy for this vulnerability requires immediate action from affected users to upgrade to the latest version of the Booktics plugin where the capability check has been properly implemented. System administrators should also implement additional monitoring controls to detect unauthorized plugin installations or modifications to the plugin directory. Network-level protections such as web application firewalls and intrusion detection systems can help identify and block malicious requests attempting to exploit this vulnerability. Security hardening measures including disabling unnecessary plugin functionality and implementing strict file permissions can further reduce the risk. Organizations should also conduct regular vulnerability assessments of their WordPress installations to identify and remediate similar authorization flaws in other plugins and themes. The vulnerability demonstrates the critical importance of proper capability validation in web applications, as outlined in the ATT&CK framework under T1078 for Valid Accounts and T1547 for Registry Run Keys and Startup Folder. This case underscores the necessity of following secure coding practices and conducting regular security reviews of plugin and theme code to prevent similar authorization bypass vulnerabilities from being introduced into production systems.