CVE-2026-27943
📋 TL;DR
OpenEMR versions up to 8.0.0 contain an authorization bypass vulnerability in the eye exam module. Authenticated users can access or modify any patient's eye exam data by manipulating form IDs, potentially exposing sensitive medical information. This affects all OpenEMR deployments using vulnerable versions.
💻 Affected Systems
- OpenEMR
📦 What is this software?
Openemr by Open Emr
⚠️ Risk & Real-World Impact
Worst Case
Malicious healthcare staff could access, modify, or delete any patient's eye exam records, leading to medical errors, privacy violations, and potential HIPAA breaches affecting thousands of patients.
Likely Case
Unauthorized viewing of patient eye exam data by authenticated users with legitimate access to some patient records but not others, violating patient privacy and confidentiality.
If Mitigated
With proper access controls and monitoring, impact is limited to attempted unauthorized access that can be detected and investigated.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward via parameter manipulation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Main branch after commit c87489bf63f2701b634d948279e104f2ed3df1c0
Vendor Advisory: https://github.com/openemr/openemr/security/advisories/GHSA-q96x-qw99-6xq9
Restart Required: Yes
Instructions:
1. Update to latest main branch from GitHub repository
2. Apply commit c87489bf63f2701b634d948279e104f2ed3df1c0
3. Restart web server and application services
4. Verify proper authorization checks are now enforced
🔧 Temporary Workarounds
Disable eye_mag module
allTemporarily disable the vulnerable eye exam module to prevent exploitation
# Modify OpenEMR configuration to disable eye_mag module
# Location varies by installation - typically in interface/modules/zend_modules/configs/application.config.php
Web Application Firewall rules
linuxImplement WAF rules to block suspicious form_id parameter manipulation
# Example ModSecurity rule:
# SecRule ARGS:form_id "@rx \d+" "phase:2,deny,id:1001,msg:'Potential eye_mag exploit attempt'"
🧯 If You Can't Patch
- Implement strict access logging and monitoring for eye_mag module access patterns
- Enforce principle of least privilege and review all user access to patient data
🔍 How to Verify
Check if Vulnerable:
Test if authenticated user can access eye exam data for patients outside their assigned caseload by modifying form_id parameter in eye_mag requestsCheck Version:
Check OpenEMR version in interface/globals.php or via admin interfaceVerify Fix Applied:
Verify that authorization checks now properly validate patient/encounter context before allowing eye exam data access📡 Detection & Monitoring
Log Indicators:
- Multiple failed authorization attempts for eye_mag module
- Rapid form_id parameter changes in eye exam requests
- Access to patient IDs outside user's normal caseload
Network Indicators:
- Unusual patterns of eye_mag API requests with varying form_id parameters
SIEM Query:
source="openemr_logs" AND (module="eye_mag" OR uri="*eye_mag*") AND (form_id_changes > threshold OR patient_id NOT IN user_assigned_patients)