CVE-2024-9528 in Contact Form Plugin by Fluent Forms for Quiz
Summary
by MITRE • 10/05/2024
The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via form label fields in all versions up to, and including, 5.1.19 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with access to edit forms (administrator by default), to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/08/2025
The vulnerability identified as CVE-2024-9528 affects the Contact Form Plugin by Fluent Forms, a widely used WordPress plugin for creating quizzes, surveys, and drag-and-drop form builders. This plugin has been installed on numerous WordPress websites, making the potential impact of this vulnerability significant across multiple organizations. The vulnerability exists within the form label fields functionality, specifically in versions up to and including 5.1.19, where the plugin fails to properly sanitize user inputs and escape output before rendering form elements on web pages.
The technical flaw stems from insufficient input validation and output escaping mechanisms within the plugin's form handling code. When administrators or users with sufficient privileges create or modify form labels, the plugin does not adequately sanitize the input data before storing it in the database. This allows malicious actors to inject malicious scripts directly into form label fields. The vulnerability is classified as stored cross-site scripting because the malicious code is permanently stored within the plugin's database and executed whenever the affected page is loaded, rather than requiring a one-time injection. This makes the attack persistent and potentially more dangerous as it affects all users who access pages containing the compromised form elements.
The operational impact of this vulnerability is substantial for WordPress administrators and website owners who rely on the Fluent Forms plugin for their online data collection needs. Attackers with administrator-level access or any user with form editing privileges can inject malicious JavaScript code that executes in the context of other users' browsers. This could enable attackers to steal session cookies, perform actions on behalf of users, redirect users to malicious websites, or even exfiltrate sensitive data from forms. The vulnerability particularly affects organizations that handle sensitive information through their WordPress forms, including personal data, business information, or confidential survey responses. The stored nature of the XSS means that once a malicious script is injected, it will continue to execute for all users who access the affected pages until the malicious code is removed from the database.
Mitigation strategies for this vulnerability should prioritize immediate patching of the Fluent Forms plugin to version 5.1.20 or later, which contains the necessary security fixes. Organizations should also implement additional security measures such as restricting user permissions to only those necessary for their roles, monitoring form creation and modification activities, and conducting regular security audits of WordPress plugins. The vulnerability aligns with CWE-79 (Cross-site Scripting) and represents a clear violation of secure coding practices as outlined in the OWASP Top Ten. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing via Service) and T1059.007 (Command and Scripting Interpreter: JavaScript) as attackers could leverage this vulnerability to execute malicious JavaScript in user browsers. Additionally, implementing Content Security Policy headers and regular input validation checks can provide additional defense-in-depth measures against similar vulnerabilities in the future.