CVE-2023-5343 in Popup Box Plugin
Summary
by MITRE • 11/20/2023
The Popup box WordPress plugin before 3.7.9 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Cross-Site Scripting attacks even when unfiltered_html is disallowed.
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Analysis
by VulDB Data Team • 04/21/2025
The vulnerability identified as CVE-2023-5343 affects the Popup box WordPress plugin version 3.7.8 and earlier, representing a critical cross-site scripting weakness that undermines the security posture of affected WordPress installations. This flaw resides in the plugin's failure to properly sanitise and escape user-controllable settings within its administrative interface, creating a persistent vector for malicious code injection that can be exploited by users with administrative privileges. The vulnerability specifically targets the plugin's handling of input data that flows into HTML output contexts without adequate validation or sanitisation measures.
The technical implementation of this vulnerability stems from improper input validation within the plugin's settings management system where user-supplied data is directly rendered into web pages without appropriate escaping mechanisms. This oversight allows malicious actors with administrator-level access to inject malicious scripts that can execute in the context of other users' browsers when they interact with the plugin's administrative interface. The vulnerability is particularly concerning because it operates even when WordPress's unfiltered_html capability has been restricted for administrators, which is a standard security hardening measure designed to prevent XSS attacks through administrative interfaces. The flaw demonstrates a failure in the plugin's output escaping routines and input sanitisation protocols, creating a persistent security gap that bypasses WordPress's built-in protections.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers with administrative access to potentially escalate their privileges or compromise the entire WordPress installation. The XSS attack vector can be leveraged to steal session cookies, redirect users to malicious sites, or perform actions on behalf of other administrators. Given that the vulnerability affects the plugin's administrative settings, successful exploitation could allow attackers to modify plugin configurations, inject malicious content into popups, or even establish persistent backdoors within the WordPress environment. This represents a significant risk to organizations relying on the Popup box plugin, particularly those with multiple administrator accounts where the attack surface is expanded.
Security mitigations for this vulnerability require immediate plugin updates to version 3.7.9 or later, which contain the necessary sanitisation and escaping fixes. Organizations should also implement additional defensive measures including regular security audits of installed plugins, monitoring for unusual administrative activities, and ensuring that all administrative accounts are protected with strong authentication mechanisms. The vulnerability aligns with CWE-79 which describes cross-site scripting flaws in web applications, and maps to ATT&CK technique T1059.007 for script execution through web shells or malicious scripts. Administrators should also consider implementing web application firewalls and content security policies to provide additional layers of protection against similar vulnerabilities in other components of their WordPress installations.