CVE-2025-21624
📋 TL;DR
ClipBucket V5 has a file upload vulnerability in the Manage Playlist functionality that allows attackers to upload PHP script files disguised as playlist cover images. This can lead to webshell deployment and remote code execution on affected servers. Both admin and regular user accounts can exploit this vulnerability.
💻 Affected Systems
- ClipBucket V5
📦 What is this software?
Clipbucket by Oxygenz
⚠️ Risk & Real-World Impact
Worst Case
Full server compromise leading to data theft, ransomware deployment, or use as part of a botnet
Likely Case
Webshell installation allowing persistent access, data exfiltration, and lateral movement
If Mitigated
File upload attempts blocked with proper validation, no impact
🎯 Exploit Status
Requires user account access but exploit is simple - just upload PHP file with image extension
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.5.1-239
Vendor Advisory: https://github.com/MacWarrior/clipbucket-v5/security/advisories/GHSA-98vm-2xqm-xrcc
Restart Required: No
Instructions:
1. Backup your installation and database. 2. Download version 5.5.1-239 from official repository. 3. Replace affected files with patched versions. 4. Verify file upload validation is working.
🔧 Temporary Workarounds
Web Server File Extension Restriction
linuxConfigure web server to block execution of PHP files in upload directories
For Apache: Add 'php_flag engine off' to .htaccess in upload directories
For Nginx: Add 'location ~ \.php$ { deny all; }' to upload directory config
File Upload Directory Isolation
linuxMove upload directories outside web root and serve via PHP script
mkdir -p /var/uploads/clipbucket
chmod 755 /var/uploads/clipbucket
Update ClipBucket config to use new upload path
🧯 If You Can't Patch
- Disable playlist cover image upload functionality entirely
- Implement WAF rules to block PHP file uploads and suspicious POST requests to upload endpoints
🔍 How to Verify
Check if Vulnerable:
Check if version is below 5.5.1-239 and test uploading a PHP file with image extension to playlist cover uploadCheck Version:
Check includes/version.php or admin area dashboard for version numberVerify Fix Applied:
Attempt to upload PHP file with image extension - should be rejected with proper error message📡 Detection & Monitoring
Log Indicators:
- PHP file upload attempts to upload endpoints
- Unusual file extensions in upload logs
- Webshell access patterns in access logs
Network Indicators:
- POST requests with PHP content to upload endpoints
- Suspicious file uploads with image extensions
SIEM Query:
source="web_logs" AND (uri="/upload" OR uri="/manage_playlist") AND (file_extension="php" OR content_type="application/x-php")