CVE-2021-27394
📋 TL;DR
This vulnerability allows authenticated non-administrative users in Mendix applications to manipulate their user roles and gain administrative privileges. It affects Mendix applications running vulnerable versions of Mendix 7, 8, and 9 platforms. The attack requires authenticated access but can lead to complete system compromise.
💻 Affected Systems
- Mendix Applications
📦 What is this software?
Mendix by Mendix
Mendix by Mendix
Mendix by Mendix
Mendix by Mendix
Mendix by Mendix
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain full administrative control over the Mendix application, allowing them to access sensitive data, modify application logic, deploy malicious modules, and potentially pivot to other systems.
Likely Case
Malicious insiders or compromised user accounts escalate privileges to admin level, enabling data theft, business logic manipulation, and persistence within the application.
If Mitigated
With proper access controls and monitoring, privilege escalation attempts are detected and blocked before successful exploitation.
🎯 Exploit Status
Exploitation requires authenticated access but appears straightforward based on vulnerability description. No public exploit code identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Mendix 7.23.19, Mendix 8.17.0, Mendix 8.12.5, Mendix 8.6.9, Mendix 9.0.5
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-875726.pdf
Restart Required: Yes
Instructions:
1. Identify Mendix platform version. 2. Upgrade to patched version: Mendix 7 → 7.23.19+, Mendix 8 → 8.17.0+ (or 8.12.5+ for 8.12, 8.6.9+ for 8.6), Mendix 9 → 9.0.5+. 3. Redeploy application. 4. Test functionality.
🔧 Temporary Workarounds
Restrict User Role Management
allImplement additional access controls to prevent non-admin users from modifying user role assignments.
Enhanced Monitoring
allMonitor for unusual privilege escalation attempts and user role modifications.
🧯 If You Can't Patch
- Implement strict least-privilege access controls and monitor all user role changes
- Isolate vulnerable applications from sensitive systems and implement network segmentation
🔍 How to Verify
Check if Vulnerable:
Check Mendix platform version in application settings or deployment configuration. Compare against affected version ranges.Check Version:
Check Mendix Modeler version or deployment logs for platform version informationVerify Fix Applied:
Confirm platform version is updated to patched version and test that authenticated users cannot modify their privileges.📡 Detection & Monitoring
Log Indicators:
- Unexpected user role changes
- Authentication logs showing privilege escalation attempts
- Admin actions from non-admin accounts
Network Indicators:
- Unusual API calls to user management endpoints from non-admin users
SIEM Query:
source="mendix_logs" AND (event="role_change" OR event="privilege_escalation") AND user_role!="admin"