Custom Field Suite Vulnerability- Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2024-0689 | WordPress Plugin Vulnerability Report

Plugin Name: Custom Field Suite

Key Information:

  • Software Type: Plugin
  • Software Slug: custom-field-suite
  • Software Status: Active
  • Software Author: mgibbs189
  • Software Downloads: 590,448
  • Active Installs: 50,000
  • Last Updated: February 28, 2024
  • Patched Versions: 2.6.5
  • Affected Versions: <= 2.6.4

Vulnerability Details:

  • Name: Custom Field Suite <= 2.6.4
  • Title: Authenticated (Admin+) Stored Cross-Site Scripting
  • Type: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N
  • CVE: CVE-2024-0689
  • CVSS Score: 4.4
  • Publicly Published: February 28, 2024
  • Researcher: Sh
  • Description: The Custom Field Suite plugin, a popular tool among WordPress users for custom field management, has been identified with a critical vulnerability in versions up to and including 2.6.4. This vulnerability stems from inadequate input sanitization and output escaping on meta values, allowing authenticated attackers with administrator-level permissions to inject malicious scripts. These scripts can then be executed whenever a user accesses a compromised page, posing a significant security risk, particularly in multi-site installations or environments where unfiltered_html is disabled.


The Custom Field Suite plugin for WordPress contains a vulnerability in versions up to and including 2.6.4, which enables authenticated admin-level users to perform Stored Cross-Site Scripting attacks via meta imports. This security flaw has been effectively addressed in the recently released version 2.6.5.

Detailed Overview:

This security issue was discovered by a researcher known as Sh, who highlighted the plugin's failure to properly sanitize input and escape output for meta values. This oversight makes it feasible for attackers with sufficient permissions to introduce harmful scripts into web pages, compromising the site's integrity and the safety of its users. The specific conditions under which this vulnerability can be exploited—namely, within multi-site setups or where unfiltered_html is restricted—underscore the nuanced nature of WordPress security and the need for comprehensive protective measures.

Advice for Users:

  • Immediate Action: Users of the Custom Field Suite plugin are strongly encouraged to update to version 2.6.5 immediately to mitigate the risk associated with this vulnerability.
  • Check for Signs of Vulnerability: Administrators should review their sites for any unusual content or behavior that may indicate a successful exploitation of this vulnerability, especially in multi-site environments.
  • Alternate Plugins: Considering the potential risks, users may explore alternative plugins that offer similar functionality but with a stronger emphasis on security, particularly those with a consistent track record of timely updates and patches.
  • Stay Updated: The cornerstone of maintaining a secure WordPress site is the diligent updating of all plugins and themes. Users should regularly check for updates and apply them without delay to protect against known vulnerabilities.


The swift identification and patching of the Stored Cross-Site Scripting vulnerability in the Custom Field Suite plugin underscore the critical importance of maintaining up-to-date software on WordPress sites. By promptly applying security updates and adopting best practices for site management, users can significantly enhance the security of their online presence. This incident serves as a reminder of the ongoing vigilance required to safeguard digital assets in an increasingly complex cyber landscape.


In today's digital ecosystem, the security of online platforms is not just a priority but a necessity. The recent discovery of a critical vulnerability in the widely-used Custom Field Suite plugin for WordPress, tagged as CVE-2024-0689, casts a spotlight on the ever-present cyber threats that loom over digital assets. This vulnerability, stemming from inadequate input sanitization and output escaping, allows authenticated users with administrator-level permissions to inject harmful scripts, compromising site integrity and user security. This issue is particularly acute in multi-site setups or environments where strict content filters are disabled, posing a significant risk to the WordPress community.

Custom Field Suite: A Cornerstone Plugin

Custom Field Suite, developed by mgibbs189, is an indispensable tool for over 50,000 WordPress sites, enabling robust custom field management. With 590,448 downloads, its utility and functionality have made it a favorite among website developers. However, the revelation of CVE-2024-0689 in versions up to and including 2.6.4 brings to light the vulnerabilities even the most trusted plugins can harbor.

Deciphering CVE-2024-0689

CVE-2024-0689 exposes a vulnerability where authenticated admin-level users can perform Stored Cross-Site Scripting (XSS) attacks through meta imports. Discovered by a researcher named Sh, this flaw has been publicly documented since February 28, 2024, and carries a CVSS score of 4.4, indicating a medium-level threat. The vulnerability's potential to compromise site integrity and user safety necessitates immediate attention.

Risks and Potential Impacts

The primary risk of CVE-2024-0689 lies in the unauthorized execution of malicious scripts, which could lead to data breaches, unauthorized access to sensitive information, and a tarnished website reputation. For businesses, this could mean the loss of consumer trust, potential legal implications, and financial losses. The specificity of the vulnerability to multi-site installations or those with disabled unfiltered_html capabilities adds a layer of complexity to its remediation.

Remediation Steps

To mitigate the risks associated with CVE-2024-0689, users of Custom Field Suite must immediately update to the patched version 2.6.5. Website administrators should also conduct thorough reviews for any unusual site behavior or unauthorized content modifications, indicative of a successful exploitation. Considering alternative plugins with a strong security track record or enhanced functionalities might also be prudent for long-term site security.

Historical Context

This is not the first time Custom Field Suite has faced security scrutiny; with three previous vulnerabilities reported since March 12, 2015, the plugin's history underscores the critical need for ongoing vigilance and prompt updates in the face of emerging threats.

The Imperative of Security Vigilance

For small business owners juggling myriad responsibilities, staying abreast of every security update and potential vulnerability might seem daunting. Yet, the digital landscape's inherent risks make it imperative. Regular updates, vigilant monitoring for unusual site activity, and a proactive approach to digital security are non-negotiable components of modern web management. The case of CVE-2024-0689 serves as a reminder of the dynamic nature of web security and the continuous need for diligence to safeguard online assets against evolving cyber threats. In this digital age, ensuring the security of your WordPress site is not just about protecting your business; it's about preserving the trust and confidence of your users.

Staying Secure

Staying on top of WordPress security can feel overwhelming for small business owners without dedicated IT staff. At Your WP Guy, we exist to shoulder that burden for you. Our WordPress experts can fully audit, secure, maintain and support your site - so you can focus on growing your business with peace of mind.

Don't tackle security risks alone. Let us help you assess any impact from this vulnerability, update your plugins, and implement ongoing maintenance to avoid future threats. We treat your website like it's our own - because we know how critical it is for reaching your customers.

Get in touch for a free consultation today on making WordPress security stress-free. Call 678-995-5169 or book a call here. Our knowledgeable team is ready to help you safeguard your online presence.

Custom Field Suite Vulnerability- Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2024-0689 | WordPress Plugin Vulnerability Report FAQs

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