CVE-2024-9940
📋 TL;DR
The Calculated Fields Form WordPress plugin up to version 5.2.45 is vulnerable to HTML injection via form submissions. Unauthenticated attackers can inject arbitrary HTML that renders when administrators view form submissions in email. This affects all WordPress sites using vulnerable plugin versions.
💻 Affected Systems
- Calculated Fields Form WordPress Plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could inject malicious HTML/JavaScript that executes in administrator email clients, potentially leading to credential theft, session hijacking, or further compromise of the WordPress admin panel.
Likely Case
Attackers inject phishing forms, malicious redirects, or defacement content that appears in administrator email notifications, potentially tricking admins into taking harmful actions.
If Mitigated
With proper email client security settings and admin awareness, injected HTML would be sanitized or displayed without execution, limiting impact to visual spam.
🎯 Exploit Status
Exploitation requires no authentication and minimal technical skill - attackers simply submit forms containing HTML payloads.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.2.46 or later
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find 'Calculated Fields Form'. 4. Click 'Update Now' if available, or download version 5.2.46+ from WordPress repository. 5. Activate updated plugin.
🔧 Temporary Workarounds
Disable Form Email Notifications
allTemporarily disable email notifications for form submissions to prevent HTML rendering in admin emails.
Enable Email HTML Filtering
allConfigure email clients to display emails as plain text only or enable strict HTML filtering.
🧯 If You Can't Patch
- Disable the Calculated Fields Form plugin entirely until patched.
- Implement web application firewall rules to block HTML patterns in form submissions.
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Installed Plugins for Calculated Fields Form version. If version is 5.2.45 or lower, system is vulnerable.Check Version:
wp plugin list --name='calculated-fields-form' --field=version (if WP-CLI installed)Verify Fix Applied:
Verify plugin version is 5.2.46 or higher in WordPress admin panel. Test form submissions with HTML content to confirm sanitization.📡 Detection & Monitoring
Log Indicators:
- Unusual HTML patterns in form submission logs
- Increased form submissions with <script>, <iframe>, or other HTML tags
Network Indicators:
- HTTP POST requests to form endpoints containing HTML payloads
SIEM Query:
source="wordpress.log" AND "calculated-fields-form" AND ("<script>" OR "<iframe>" OR "javascript:")