CVE-2026-23795
📋 TL;DR
This CVE describes an XXE vulnerability in Apache Syncope Console that allows administrators with Keymaster parameter privileges to inject malicious XML. Successful exploitation could lead to sensitive data leakage. Affected versions are Apache Syncope 3.0 through 3.0.15 and 4.0 through 4.0.3.
💻 Affected Systems
- Apache Syncope Console
⚠️ Risk & Real-World Impact
Worst Case
Administrator-level attacker could exfiltrate sensitive server files, database credentials, or internal network information via XXE.
Likely Case
Privileged insider or compromised admin account could read configuration files containing secrets or sensitive data.
If Mitigated
With proper access controls and network segmentation, impact limited to data accessible to the Syncope application user.
🎯 Exploit Status
Exploitation requires admin-level access to the Console interface. XXE payloads are well-documented and easy to construct.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.0.16 or 4.0.4
Vendor Advisory: https://lists.apache.org/thread/mzgbdn8hzk8vr94o660njcc7w62c2pos
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download patched version from Apache Syncope website. 3. Stop Syncope service. 4. Replace with patched version. 5. Restart Syncope service. 6. Verify version upgrade.
🔧 Temporary Workarounds
Disable DTD processing
allConfigure XML parser to disable external entity resolution
Set XML parser properties: FEATURE_SECURE_PROCESSING=true, disallow-doctype-decl=true
Restrict Keymaster parameter access
allRemove Keymaster parameter creation/edit entitlements from admin roles
Modify role definitions in Syncope configuration to remove 'Keymaster' entitlements
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Syncope Console from sensitive systems
- Enable detailed logging and monitoring for XML parsing errors or unusual admin activities
🔍 How to Verify
Check if Vulnerable:
Check Apache Syncope version via admin interface or configuration files. If version is between 3.0-3.0.15 or 4.0-4.0.3, system is vulnerable.Check Version:
Check Syncope web interface admin panel or examine syncope-core-VERSION.jar fileVerify Fix Applied:
After patching, verify version shows 3.0.16 or 4.0.4. Test Keymaster parameter functionality with safe XML data.📡 Detection & Monitoring
Log Indicators:
- XML parsing errors containing external entity references
- Unusual admin activity creating/modifying Keymaster parameters
- Large outbound data transfers from Syncope process
Network Indicators:
- HTTP requests to internal systems from Syncope server
- DNS requests for unusual external domains from Syncope
SIEM Query:
source="syncope.log" AND ("XXE" OR "external entity" OR "DOCTYPE")