CVE-2026-23794
📋 TL;DR
This reflected XSS vulnerability in Apache Syncope's Enduser Login page allows attackers to steal user credentials by tricking legitimate users into clicking malicious links. It affects Apache Syncope versions 3.0 through 3.0.15 and 4.0 through 4.0.3. Successful exploitation requires user interaction but can lead to credential theft.
💻 Affected Systems
- Apache Syncope
📦 What is this software?
Syncope by Apache
Syncope by Apache
⚠️ Risk & Real-World Impact
Worst Case
Attackers steal administrative credentials, gaining full control over the Syncope instance and potentially accessing sensitive identity management data.
Likely Case
Attackers steal regular user credentials, enabling unauthorized access to user accounts and potentially escalating privileges within the system.
If Mitigated
With proper input validation and output encoding, the malicious script payloads would be neutralized, preventing credential theft.
🎯 Exploit Status
Reflected XSS attacks are well-understood and easy to weaponize; exploitation requires social engineering to trick users into clicking malicious links.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.0.16 or 4.0.4
Vendor Advisory: https://lists.apache.org/thread/7h30ghqdsf3spl3h7gdmscxofrm8ygjo
Restart Required: Yes
Instructions:
1. Download Apache Syncope 3.0.16 or 4.0.4 from official Apache repositories. 2. Backup current configuration and data. 3. Stop the Syncope service. 4. Replace with patched version. 5. Restart the service.
🔧 Temporary Workarounds
Web Application Firewall (WAF)
allDeploy a WAF with XSS protection rules to block malicious payloads before they reach the application.
Input Validation Filter
allImplement custom input validation to sanitize user inputs on the Enduser Login page.
🧯 If You Can't Patch
- Implement Content Security Policy (CSP) headers to restrict script execution sources.
- Deploy network segmentation to limit access to the Syncope instance to trusted users only.
🔍 How to Verify
Check if Vulnerable:
Check if your Apache Syncope version is between 3.0-3.0.15 or 4.0-4.0.3 using the version check command.Check Version:
Check the Syncope web interface admin panel or review application logs for version information.Verify Fix Applied:
After patching, verify the version is 3.0.16 or 4.0.4 and test the Enduser Login page with XSS payloads to ensure they are properly sanitized.📡 Detection & Monitoring
Log Indicators:
- Unusual GET requests with script tags or JavaScript payloads in query parameters to the Enduser Login page.
- Multiple failed login attempts from unexpected IP addresses following suspicious requests.
Network Indicators:
- HTTP requests containing malicious script payloads in URL parameters directed at the Syncope Enduser Login endpoint.
SIEM Query:
source="apache_syncope" AND (url="*enduser/login*" AND (param="*<script>*" OR param="*javascript:*"))