CVE-2021-4357 in uListing Plugin
Summary
by MITRE • 06/07/2023
The uListing plugin for WordPress is vulnerable to authorization bypass due to missing capability checks, and a missing security nonce, on the UlistingUserRole::save_role_api function in versions up to, and including, 1.6.6. This makes it possible for unauthenticated attackers to arbitrarily delete site posts and pages.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 04/09/2026
The uListing plugin for WordPress presents a critical authorization bypass vulnerability that fundamentally undermines the security model of WordPress installations. This vulnerability exists within the UlistingUserRole::save_role_api function and affects versions up to and including 1.6.6, creating a pathway for unauthenticated attackers to execute arbitrary actions on affected sites. The flaw stems from the complete absence of proper capability checks and security nonce validation, which are fundamental security mechanisms designed to prevent unauthorized modifications to WordPress content. The vulnerability represents a direct violation of the principle of least privilege, where the plugin fails to verify whether the requesting user possesses the necessary permissions to perform the requested operations.
The technical implementation of this vulnerability exploits the lack of proper authentication verification within the plugin's API endpoint. Without capability checks, any attacker can submit requests to the save_role_api function regardless of their authentication status or user role. The missing security nonce further compounds the issue by eliminating the time-based token validation that would normally prevent replay attacks and ensure request integrity. This combination creates a scenario where an unauthenticated user can craft malicious requests that bypass WordPress's core security controls, effectively granting them the ability to perform administrative actions on the site. The vulnerability operates at the application layer and leverages the plugin's API interface to access core WordPress functionality.
The operational impact of this vulnerability is severe and far-reaching for affected WordPress installations. Unauthenticated attackers can leverage this flaw to delete posts, pages, and potentially other site content, leading to data loss and service disruption. The ability to perform arbitrary deletions undermines the integrity and availability of the website, potentially causing significant business impact and reputational damage. Additionally, the vulnerability could be exploited to create further attack vectors by allowing attackers to modify user roles or permissions, potentially escalating their access to full administrative control. The exposure affects all users of the vulnerable plugin versions, regardless of their authentication status, making it particularly dangerous for publicly accessible WordPress sites.
Mitigation strategies for this vulnerability must address both the immediate security gap and the underlying architectural issues within the plugin. The primary solution involves upgrading to a patched version of the uListing plugin where proper capability checks and nonce validation have been implemented. System administrators should also implement additional monitoring and logging around the affected API endpoints to detect suspicious activity. Network-level protections such as web application firewalls can provide additional defense-in-depth by filtering malicious requests before they reach the vulnerable plugin. Organizations should also consider implementing role-based access controls and regularly auditing user permissions to minimize the potential impact of such vulnerabilities. This vulnerability aligns with CWE-863, which describes improper authorization in software, and represents a clear violation of ATT&CK technique T1078, which covers valid accounts for lateral movement. The issue demonstrates the critical importance of proper input validation and authentication mechanisms in web applications, particularly those that provide API endpoints for content management operations.