CVE-2025-49940
📋 TL;DR
This DOM-based XSS vulnerability in the Fusion Builder WordPress plugin allows attackers to inject malicious scripts into web pages viewed by other users. It affects WordPress sites using Fusion Builder versions up to 3.13.2. Attackers could steal session cookies, redirect users, or perform actions on their behalf.
💻 Affected Systems
- ThemeFusion Fusion Builder WordPress plugin
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete account takeover, data theft, or malware distribution to site visitors through persistent XSS payloads.
Likely Case
Session hijacking, credential theft, or defacement of affected web pages.
If Mitigated
Limited impact if proper Content Security Policy (CSP) headers are implemented and user input validation is enforced.
🎯 Exploit Status
Exploitation requires user interaction with maliciously crafted content. Attackers need to trick users into interacting with specific DOM elements.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 3.13.3 or later
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins > Installed Plugins. 3. Find 'Fusion Builder' and click 'Update Now'. 4. Verify update to version 3.13.3 or higher.
🔧 Temporary Workarounds
Implement Content Security Policy
allAdd CSP headers to restrict script execution sources and prevent inline script execution.
Add to .htaccess: Header set Content-Security-Policy "default-src 'self'; script-src 'self'"
Or configure in web server settings
🧯 If You Can't Patch
- Disable Fusion Builder plugin temporarily
- Restrict plugin access to trusted users only
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin > Plugins > Installed Plugins for Fusion Builder version 3.13.2 or lower.Check Version:
wp plugin list --name=fusion-builder --field=versionVerify Fix Applied:
Confirm Fusion Builder version is 3.13.3 or higher in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to fusion-builder endpoints
- Suspicious JavaScript payloads in request parameters
Network Indicators:
- Malicious script tags in HTTP requests to fusion-builder AJAX endpoints
SIEM Query:
source="wordpress.log" AND "fusion-builder" AND ("script" OR "javascript" OR "onerror")