CVE-2026-25135 Overview
CVE-2026-25135 is an information disclosure vulnerability in OpenEMR, a free and open source electronic health records (EHR) and medical practice management application. The vulnerability allows unauthorized access to complete contact information for all users, organizations, and patients in the system when exploited by an attacker with specific FHIR API capabilities.
Critical Impact
Complete disclosure of sensitive patient and organizational contact information through the FHIR Bulk Data Export API, potentially affecting healthcare organizations using OpenEMR since 2023.
Affected Products
- OpenEMR versions prior to 8.0.0
- OpenEMR installations with FHIR API enabled since 2023
- Systems with confidential clients granted system/Location.read scope
Discovery Timeline
- 2026-02-25 - CVE-2026-25135 published to NVD
- 2026-02-25 - Last updated in NVD database
Technical Details for CVE-2026-25135
Vulnerability Analysis
This information disclosure vulnerability (CWE-200) exists within OpenEMR's FHIR (Fast Healthcare Interoperability Resources) Bulk Data Export implementation. The flaw enables unauthorized extraction of comprehensive contact details for all entities in the healthcare system, including patients, healthcare providers, and affiliated organizations.
The vulnerability specifically impacts the bulk export operations when a client application possesses certain capability combinations. While the attack requires high privileges and user interaction, successful exploitation results in high confidentiality impact, potentially exposing protected health information (PHI) in violation of HIPAA and other healthcare data protection regulations.
Root Cause
The root cause lies in improper access control within OpenEMR's FHIR API implementation. When processing bulk export requests with the system/(Group,Patient,*).$export operation combined with system/Location.read capabilities, the application fails to properly restrict the scope of data returned. This allows the Location resource data, which contains full contact information for all system entities, to be included in export operations without appropriate filtering.
Attack Vector
The vulnerability is exploitable over the network, though it requires several prerequisites that limit practical exploitation to high-trust environments:
- Confidential Client Access: The attacker must have access to a confidential OAuth2 client configured with secure key exchange
- Administrator Enablement: An administrator must have explicitly enabled and granted permissions to the application
- Specific Scope Assignment: The client must possess both the bulk export operation capability and system/Location.read scope
In practice, this attack vector is most relevant in server-to-server communication scenarios between trusted healthcare systems that have established legal data sharing agreements. An attacker with compromised credentials to such a system, or a malicious insider with access to an authorized client application, could leverage these capabilities to extract the complete patient directory.
The exploitation involves making authenticated FHIR Bulk Data Export API requests. When the vulnerable scopes are present, the response includes Location resources containing full contact details that should otherwise be restricted based on the intended data access boundaries.
Detection Methods for CVE-2026-25135
Indicators of Compromise
- Unusual volume of FHIR Bulk Data Export requests from confidential clients
- Export operations returning Location resources with complete contact information
- API access patterns showing systematic extraction of patient directory data
- Unexpected access to system/Location.read scope by client applications
Detection Strategies
- Monitor FHIR API logs for bulk export operations involving Location resources
- Implement alerting on confidential client activity accessing sensitive scopes
- Review OAuth2 client configurations for overly permissive scope assignments
- Audit server-to-server communication patterns for data exfiltration indicators
Monitoring Recommendations
- Enable comprehensive logging for all FHIR API bulk export operations
- Configure alerts for export requests that include patient and organizational contact data
- Regularly review and audit confidential client scope assignments
- Monitor for unusual data volume in bulk export responses
How to Mitigate CVE-2026-25135
Immediate Actions Required
- Upgrade OpenEMR to version 8.0.0 or later immediately
- Review all confidential client applications for system/Location.read scope assignments
- Audit recent FHIR bulk export operations for potential data exposure
- Assess whether any unauthorized data disclosure has occurred and initiate incident response if needed
Patch Information
OpenEMR has released version 8.0.0 which contains the security fix for this vulnerability. The patch is available in GitHub Commit 7ab23dfe73ebd16dd66a526272f3761f1bd5be7d. Organizations should review the GitHub Security Advisory for complete details on the vulnerability and remediation steps.
Workarounds
- Disable all confidential clients that have been granted the vulnerable scopes until patching is complete
- Restrict client applications to exclude the system/Location.read scope
- Implement additional network-level controls to limit FHIR API access to trusted endpoints
- Consider temporarily disabling bulk export functionality if not operationally critical
# Review OAuth2 client scopes in OpenEMR database
# Identify clients with system/Location.read scope
mysql -u openemr_user -p openemr_db -e "SELECT client_name, scope FROM oauth_clients WHERE scope LIKE '%system/Location.read%';"
# Disable vulnerable scopes until patch is applied
# Update client configurations to remove system/Location.read
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
