CVE-2025-48827
📋 TL;DR
This vulnerability allows unauthenticated attackers to invoke protected API controller methods in vBulletin, potentially leading to remote code execution. It affects vBulletin installations running PHP 8.1 or later. All vBulletin 5.0.0-5.7.5 and 6.0.0-6.0.3 installations are vulnerable.
💻 Affected Systems
- vBulletin
📦 What is this software?
Vbulletin by Vbulletin
Vbulletin by Vbulletin
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Unauthenticated attackers gain administrative access, modify content, steal user data, or execute arbitrary code.
If Mitigated
Attackers can still access protected API methods but impact is limited by additional security controls.
🎯 Exploit Status
Actively exploited in the wild since May 2025. Simple HTTP requests to /api.php with specific parameters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: vBulletin 5.7.6 and 6.0.4
Vendor Advisory: https://www.vbulletin.com/forum/forum/vbulletin-announcements/vbulletin-announcements_aa/4471420-vbulletin-5-7-6-and-6-0-4-security-update
Restart Required: No
Instructions:
1. Download vBulletin 5.7.6 or 6.0.4 from the official customer area. 2. Backup your database and files. 3. Upload new files to your server. 4. Run upgrade.php. 5. Clear system cache.
🔧 Temporary Workarounds
Downgrade PHP Version
linuxTemporarily downgrade to PHP 7.x to mitigate the vulnerability
sudo apt install php7.4
sudo a2dismod php8.1
sudo a2enmod php7.4
sudo systemctl restart apache2
Block API Access
allBlock access to /api.php via web server configuration
# Apache: <Location "/api.php"> Require all denied </Location>
# Nginx: location = /api.php { deny all; }
🧯 If You Can't Patch
- Implement strict network segmentation and isolate vBulletin servers
- Deploy WAF rules to block requests to /api.php with suspicious parameters
🔍 How to Verify
Check if Vulnerable:
Check if /api.php?method=replaceAdTemplate returns data without authentication on PHP 8.1+Check Version:
Check AdminCP → Maintenance → View PHP Info for PHP version, and AdminCP → Products for vBulletin versionVerify Fix Applied:
Verify the same request returns proper authentication error after patching📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /api.php with method=replaceAdTemplate or other protected methods
- Unauthenticated API calls returning 200 OK
Network Indicators:
- Unusual traffic to /api.php endpoint from external IPs
- POST/GET requests with method parameter to API
SIEM Query:
source="web_logs" AND uri_path="/api.php" AND (http_method="POST" OR http_method="GET") AND query_string="*method=*" AND NOT user_agent="*bot*"