CVE-2025-47916
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to execute arbitrary PHP code on Invision Community installations by sending crafted template strings to the themeeditor.php endpoint. The flaw exists in the customCss method which improperly passes user input to the template engine for evaluation. All Invision Community 5.0.0 through 5.0.6 installations with internet-facing access are affected.
💻 Affected Systems
- Invision Community
📦 What is this software?
Invisioncommunity by Invisioncommunity
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary commands, steal sensitive data, install malware, pivot to internal networks, and maintain persistent access.
Likely Case
Website defacement, data theft, installation of backdoors or cryptocurrency miners, and potential lateral movement within the hosting environment.
If Mitigated
Limited impact if proper network segmentation, web application firewalls, and intrusion detection systems are in place to block exploitation attempts.
🎯 Exploit Status
Exploitation requires sending a crafted HTTP POST request to the vulnerable endpoint. Multiple public proof-of-concept exploits are available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.0.7
Vendor Advisory: https://invisioncommunity.com/release-notes-v5/507-r41/
Restart Required: No
Instructions:
1. Backup your Invision Community installation and database. 2. Download Invision Community 5.0.7 from the official vendor. 3. Upload and overwrite all files with the patched version. 4. Run the upgrade script if prompted. 5. Verify the installation is now version 5.0.7.
🔧 Temporary Workarounds
Block themeeditor.php access
allTemporarily block access to the vulnerable endpoint using web server configuration or firewall rules.
# For Apache: add to .htaccess
<Files "themeeditor.php">
Order allow,deny
Deny from all
</Files>
# For Nginx: add to server block
location ~ /themeeditor\.php$ {
deny all;
return 403;
}
Web Application Firewall rule
allAdd a WAF rule to block requests containing template engine syntax patterns in POST parameters.
# ModSecurity rule example
SecRule ARGS_POST "\{.*\}" "id:1001,phase:2,deny,msg:'Potential template injection attempt'"
# Cloudflare WAF: Create rule blocking requests with '{' and '}' in POST body to themeeditor.php
🧯 If You Can't Patch
- Implement strict network access controls to limit access to the Invision Community installation to trusted IP addresses only.
- Deploy a web application firewall with rules specifically designed to detect and block template injection attempts.
🔍 How to Verify
Check if Vulnerable:
Check if your Invision Community version is between 5.0.0 and 5.0.6 by logging into the Admin Control Panel and viewing the version information.Check Version:
# Check version via Admin CP or by examining the /admin/upgrade directory for version filesVerify Fix Applied:
After patching, verify the version shows 5.0.7 in the Admin Control Panel and test that themeeditor.php no longer accepts template injection payloads.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /themeeditor.php with unusual parameters
- Requests containing template syntax like {php} or {expression} in POST data
- Sudden increase in 403 errors if workarounds are implemented
Network Indicators:
- Unusual outbound connections from the web server
- Traffic patterns indicating command and control communication
- POST requests to themeeditor.php from unexpected IP addresses
SIEM Query:
source="web_server_logs" AND (uri_path="/themeeditor.php" AND http_method="POST" AND (request_body CONTAINS "{php}" OR request_body CONTAINS "{expression}"))