CVE-2025-41056
📋 TL;DR
This vulnerability allows authenticated attackers to inject malicious scripts into appRain CMF that execute when other users view affected pages. It affects organizations using appRain CMF version 4.0.5 for content management. The stored XSS can lead to session hijacking, credential theft, or unauthorized actions.
💻 Affected Systems
- appRain CMF
📦 What is this software?
Apprain by Apprain
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator credentials, take over administrative accounts, deface websites, or distribute malware to site visitors.
Likely Case
Attackers with authenticated access could hijack user sessions, steal cookies, or perform actions on behalf of other users.
If Mitigated
With proper input validation and output encoding, the risk is limited to minor data manipulation if other security controls fail.
🎯 Exploit Status
Exploitation requires authenticated access to the vulnerable endpoint. Attackers need to craft malicious payloads targeting the specific parameters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for patched version
Vendor Advisory: https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-apprain-cmf
Restart Required: No
Instructions:
1. Check the vendor advisory for patched version
2. Update appRain CMF to the latest secure version
3. Verify the fix by testing the vulnerable parameters
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation for the 'data[Addon][layouts]' and 'data[Addon][layouts_except]' parameters
Output Encoding
allApply proper output encoding when displaying user-controlled data from these parameters
🧯 If You Can't Patch
- Restrict access to the /apprain/developer/addons/update/hysontable endpoint to trusted administrators only
- Implement a web application firewall (WAF) with XSS protection rules
🔍 How to Verify
Check if Vulnerable:
Check if running appRain CMF version 4.0.5 and test the /apprain/developer/addons/update/hysontable endpoint with XSS payloads in the specified parametersCheck Version:
Check appRain configuration files or admin panel for version informationVerify Fix Applied:
After updating, test the same endpoint with XSS payloads to confirm they are properly sanitized📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /apprain/developer/addons/update/hysontable with script tags or JavaScript in parameters
- Multiple failed XSS attempts from same source
Network Indicators:
- HTTP requests containing 'data[Addon][layouts]' or 'data[Addon][layouts_except]' parameters with suspicious content
SIEM Query:
source="web_server" AND (uri="/apprain/developer/addons/update/hysontable" AND (param="data[Addon][layouts]" OR param="data[Addon][layouts_except]") AND content CONTAINS "<script>" OR "javascript:")