CVE-2021-24601 in WPFront Notification Bar Plugin
Summary
by MITRE • 09/06/2021
The WPFront Notification Bar WordPress plugin before 2.1.0.08087 does not properly sanitise and escape its settings, which could allow high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/09/2021
The vulnerability identified as CVE-2021-24601 affects the WPFront Notification Bar WordPress plugin, specifically versions prior to 2.1.0.08087, representing a critical cross-site scripting weakness that undermines the security posture of WordPress installations. This flaw exists within the plugin's handling of user settings, where inadequate sanitisation and escaping mechanisms fail to properly validate input data before rendering it in the browser context. The vulnerability is particularly concerning because it targets high privilege users, including administrators and editors who possess elevated permissions within the WordPress ecosystem. According to CWE-79, this represents a classic cross-site scripting vulnerability where malicious scripts can be injected into web pages viewed by other users, potentially leading to unauthorized actions performed on behalf of victims.
The technical flaw manifests when the plugin processes configuration settings that are intended to be displayed within the WordPress admin interface or rendered on frontend pages. The absence of proper sanitisation allows attackers with sufficient privileges to inject malicious JavaScript code through plugin settings, which then executes in the context of other users' browsers. Even when the WordPress environment restricts the unfiltered_html capability for most users, this vulnerability circumvents such protections by targeting the plugin's own settings handling mechanisms. The vulnerability operates at the application layer and can be exploited through the WordPress admin panel where settings are saved and subsequently displayed, creating a persistent threat vector that can affect all users who view pages containing the notification bar.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data exfiltration, and privilege escalation within the WordPress environment. High privilege users who are targeted by this vulnerability may have their credentials compromised or their administrative capabilities abused, potentially leading to complete compromise of the WordPress installation. The attack surface is particularly dangerous because it leverages legitimate plugin functionality to deliver malicious payloads, making detection more challenging for security monitoring systems. This vulnerability aligns with ATT&CK technique T1548.002, which involves the abuse of application permissions to gain elevated privileges, and demonstrates how plugin vulnerabilities can serve as entry points for broader system compromise.
Organizations should immediately update the WPFront Notification Bar plugin to version 2.1.0.08087 or later to remediate this vulnerability. System administrators should also implement additional security measures including regular security audits of installed plugins, monitoring for suspicious plugin settings modifications, and maintaining comprehensive backup strategies. The vulnerability highlights the importance of proper input validation and output escaping in web applications, particularly in content management systems where plugins often handle user-provided data. Security teams should also consider implementing web application firewalls and content security policies as additional defensive measures to mitigate the risk of exploitation. The incident underscores the critical need for regular security updates and the potential consequences of outdated plugin versions in WordPress environments.