CVE-2025-56704
📋 TL;DR
LeptonCMS 7.3.0 contains an arbitrary file upload vulnerability due to insufficient file validation. Authenticated attackers can upload malicious ZIP/PHP files to achieve remote code execution. This affects all systems running the vulnerable version.
💻 Affected Systems
- LeptonCMS
📦 What is this software?
Leptoncms by Lepton Cms
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise through remote code execution, data theft, and complete control of the web server.
Likely Case
Webshell deployment leading to data exfiltration, lateral movement, and persistence on the server.
If Mitigated
Limited impact with proper file upload restrictions and web application firewalls in place.
🎯 Exploit Status
Multiple proof-of-concept documents are publicly available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://lepton.com
Restart Required: No
Instructions:
1. Check vendor website for security updates. 2. Apply any available patches. 3. Verify file upload functionality is secured.
🔧 Temporary Workarounds
Restrict File Upload Types
allConfigure web server to block execution of uploaded PHP files and restrict allowed file extensions.
# Example Apache .htaccess rule:
<FilesMatch "\.(php|phtml|phar)$">
Order Allow,Deny
Deny from all
</FilesMatch>
Implement File Upload Validation
allAdd server-side validation to check file types, extensions, and content before allowing uploads.
🧯 If You Can't Patch
- Disable file upload functionality entirely if not required.
- Implement strict network segmentation and web application firewall rules to block malicious upload patterns.
🔍 How to Verify
Check if Vulnerable:
Check if running LeptonCMS version 7.3.0 and review file upload functionality for proper validation.Check Version:
Check CMS admin panel or version.php file for version information.Verify Fix Applied:
Test file upload with malicious ZIP/PHP files to ensure they are rejected.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads with .php or .zip extensions
- Multiple failed upload attempts
- Webshell access patterns in access logs
Network Indicators:
- POST requests to upload endpoints with suspicious file content
- Unexpected outbound connections from web server
SIEM Query:
source="web_logs" AND (uri_path="*upload*" AND (file_extension="php" OR file_extension="zip"))