CVE-2026-18347 in Kirki Plugin
Summary
by MITRE • 08/16/2026
The Kirki – Freeform Page Builder, Website Builder & Customizer plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 6.1.1. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with custom-level access and above, to read arbitrary user metadata and sensitive user record fields — including email address, assigned roles, registration date, and any user_meta values — belonging to any WordPress user including administrators, by supplying a target user ID with a user-type context to the frontend collection endpoint.
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Analysis
by VulDB Data Team • 08/16/2026
The vulnerability in the Kirki plugin represents a critical authorization bypass flaw that undermines the fundamental security model of WordPress installations. This issue affects all versions up to and including 6.1.1, making it a widespread concern for thousands of WordPress sites that rely on this popular page builder and customizer plugin. The core problem lies in the plugin's failure to implement proper access control verification mechanisms when processing frontend requests, creating a pathway for malicious actors to exploit legitimate plugin functionality for unauthorized data access.
The technical implementation flaw stems from inadequate input validation and permission checking within the plugin's frontend collection endpoint. When an authenticated attacker with custom-level privileges or higher submits a request containing a target user ID alongside a user-type context parameter, the plugin fails to verify whether the requesting user has legitimate authorization to access the specified user's metadata. This oversight allows attackers to systematically enumerate user information across the entire WordPress user base without proper authorization, effectively bypassing the standard WordPress capability checks that should prevent such unauthorized access patterns.
The operational impact of this vulnerability extends far beyond simple information disclosure, as it provides attackers with comprehensive user profile data including email addresses, assigned roles, registration timestamps, and all stored user_meta values. This metadata collection capability enables sophisticated social engineering campaigns, targeted phishing attacks, and privilege escalation attempts against administrators and other high-value users within the WordPress installation. The vulnerability particularly affects sites where administrators may have elevated privileges or sensitive role assignments that could be leveraged for further compromise.
Security researchers have identified this issue as aligning with CWE-863 (Authorization Bypass) and represents a clear violation of the principle of least privilege in web application security. From an attacker perspective, this vulnerability maps directly to ATT&CK technique T1078 (Valid Accounts) and T1566 (Phishing) by enabling the acquisition of valid user credentials and associated metadata that can be used for identity deception and targeted attacks. Organizations using affected versions should immediately implement mitigation strategies including plugin updates, role-based access restrictions, and monitoring for unusual API endpoint access patterns to prevent exploitation.
The vulnerability highlights critical gaps in WordPress plugin security practices and demonstrates the importance of implementing robust access control verification even in frontend-facing components. Proper implementation would require the plugin to validate user capabilities against the target resource before processing any metadata requests, ensuring that only users with appropriate permissions can access sensitive information. Additionally, organizations should consider implementing network-level protections such as rate limiting and API endpoint monitoring to detect and prevent exploitation attempts while awaiting official patches from the plugin developers.