CVE-2024-29793 in MailChimp Forms Plugin
Summary
by MITRE • 03/27/2024
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in MailMunch MailChimp Forms by MailMunch allows Stored XSS.This issue affects MailChimp Forms by MailMunch: from n/a through 3.2.2.
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Analysis
by VulDB Data Team • 04/12/2025
The vulnerability identified as CVE-2024-29793 represents a critical cross-site scripting flaw within the MailMunch MailChimp Forms plugin, specifically impacting versions prior to 3.2.2. This stored XSS vulnerability occurs during the web page generation process when user input is not properly sanitized or neutralized before being rendered in web pages. The issue stems from the plugin's failure to adequately validate and escape user-supplied data that gets stored and subsequently executed in victim browsers, creating a persistent security risk that can affect multiple users simultaneously.
The technical implementation of this vulnerability involves the plugin's handling of form data and user-generated content within the WordPress environment. When administrators or users input data into MailMunch forms, this data is stored in the database without proper sanitization mechanisms. The flaw manifests when this stored data is later retrieved and displayed in web pages, allowing malicious scripts to be executed in the context of other users' browsers. This particular vulnerability falls under CWE-79, which specifically addresses improper neutralization of input during web page generation, making it a classic stored cross-site scripting vulnerability that can be exploited to hijack user sessions, steal sensitive information, or perform unauthorized actions on behalf of victims.
The operational impact of this vulnerability extends beyond simple data theft, as it provides attackers with the ability to establish persistent footholds within affected WordPress installations. Attackers can craft malicious input that, when processed by the vulnerable plugin, executes arbitrary JavaScript code in the browsers of unsuspecting users who visit pages containing the compromised content. This stored nature of the vulnerability means that the malicious payload remains active even after the initial injection, continuously affecting any user who accesses the affected web pages. The implications are particularly severe in environments where administrators frequently use MailMunch forms for user interaction, as the attack surface expands significantly with the number of stored form submissions.
Mitigation strategies for CVE-2024-29793 should prioritize immediate plugin updates to version 3.2.2 or later, where the XSS vulnerability has been addressed through proper input sanitization and output escaping mechanisms. Security practitioners should also implement additional defensive measures including comprehensive input validation, output encoding for all user-supplied content, and regular security audits of third-party plugins. Organizations should consider implementing content security policies to limit the execution of unauthorized scripts and establish monitoring procedures to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date WordPress plugins and the necessity of following security best practices such as those outlined in the OWASP Top Ten and NIST cybersecurity frameworks. Additionally, this vulnerability aligns with ATT&CK technique T1566, specifically focusing on the initial access phase through malicious content delivery, emphasizing the need for robust web application security controls and regular vulnerability assessments to prevent successful exploitation attempts.