CVE-2026-23627: OpenEMR SQL Injection Vulnerability

CVE-2026-23627 Overview

CVE-2026-23627 is a SQL Injection vulnerability affecting OpenEMR, a free and open source electronic health records (EHR) and medical practice management application. Prior to version 8.0.0, an authenticated user can exploit a flaw in the Immunization module to execute arbitrary SQL queries. This vulnerability stems from improper handling of user-supplied patient_id values, which are directly concatenated into SQL WHERE clauses without parameterization or escaping.

Successful exploitation can lead to complete database compromise, Protected Health Information (PHI) exfiltration, credential theft, and potential remote code execution. Given OpenEMR's role in healthcare environments and its storage of sensitive patient data, this vulnerability poses significant risk to healthcare organizations.

Critical Impact

Authenticated attackers can execute arbitrary SQL queries to exfiltrate sensitive PHI, steal credentials, and potentially achieve remote code execution through database compromise.

Affected Products

• OpenEMR versions prior to 8.0.0
• OpenEMR Immunization module

Discovery Timeline

• 2026-02-25 - CVE-2026-23627 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-23627

Vulnerability Analysis

This SQL Injection vulnerability (CWE-89) exists within the Immunization module of OpenEMR. The root issue lies in the ImmunizationTable.php file located at interface/modules/zend_modules/module/Immunization/src/Immunization/Model/. The vulnerable code constructs SQL queries by directly concatenating user-supplied patient_id values into WHERE clauses without proper sanitization or parameterized queries.

The vulnerability is accessible over the network and requires low attack complexity with no user interaction needed beyond the attacker having authenticated access to the system. Any authenticated user within the OpenEMR application can exploit this flaw, making it particularly dangerous in multi-user healthcare environments where various staff members have system access.

Root Cause

The vulnerability stems from improper input validation and the use of dynamic SQL query construction. User-supplied patient_id values are processed through the add_escape_custom() function, which proved insufficient for preventing SQL injection attacks. The code failed to implement parameterized queries, allowing attackers to break out of the intended SQL context and inject malicious SQL statements.

Attack Vector

The attack vector is network-based, targeting the Immunization module's query functionality. An authenticated attacker can manipulate the patient_id parameter to inject arbitrary SQL commands. Since the vulnerability allows execution of arbitrary SQL queries, attackers can:

1. Extract sensitive patient health information (PHI) from the database
2. Dump user credentials and password hashes
3. Modify or delete database records
4. Potentially achieve remote code execution through database-specific features (e.g., MySQL's INTO OUTFILE or stored procedures)

The following patch demonstrates the fix implemented in version 8.0.0:

         }
 
         $query .= "i.patient_id=p.pid and " .
-            add_escape_custom($query_codes) .
+            $query_codes .
             $query_pids . "i.cvx_code = c.code ORDER BY i.patient_id, i.id";
 
+        // Merge code_bind_values into query_data to use parameterized queries
+        if (!empty($form_data['code_bind_values'])) {
+            $query_data = array_merge($query_data, $form_data['code_bind_values']);
+        }
+
+        // Merge pid_bind_values into query_data to use parameterized queries
+        if (!empty($form_data['pid_bind_values'])) {
+            $query_data = array_merge($query_data, $form_data['pid_bind_values']);
+        }
+
         if ($getCount) {
             $result = $this->applicationTable->zQuery($query, $query_data);
             $resCount = $result->count();

Source: GitHub Commit cbf4ea4

The patch replaces the vulnerable add_escape_custom() approach with proper parameterized queries by merging bind values into the query data array, ensuring user input is treated as data rather than executable SQL code.

Detection Methods for CVE-2026-23627

Indicators of Compromise

• Unusual SQL query patterns in database logs containing UNION SELECT, OR 1=1, or other SQL injection payloads targeting patient_id parameters
• Unexpected database queries accessing multiple patient records or system tables from the Immunization module
• Authentication logs showing legitimate users accessing abnormally large amounts of patient data
• Database error logs indicating malformed SQL queries or syntax errors originating from the Immunization module

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect SQL injection patterns in HTTP requests to OpenEMR
• Monitor database query logs for anomalous query structures, especially those containing SQL injection signatures
• Deploy application-layer intrusion detection to identify unusual parameter values in requests to the Immunization module
• Utilize SIEM correlation rules to detect potential PHI exfiltration patterns

Monitoring Recommendations

• Enable detailed logging for all database queries executed by OpenEMR
• Configure alerts for bulk data retrieval operations that exceed normal thresholds
• Monitor network traffic for large outbound data transfers from the database server
• Implement user behavior analytics to detect anomalous access patterns by authenticated users

How to Mitigate CVE-2026-23627

Immediate Actions Required

• Upgrade OpenEMR to version 8.0.0 or later immediately
• Audit database access logs for potential exploitation attempts prior to patching
• Review user accounts for any unauthorized access or suspicious activity
• Consider rotating database credentials and application secrets as a precautionary measure

Patch Information

OpenEMR version 8.0.0 addresses this vulnerability by implementing parameterized queries for the affected Immunization module. The fix ensures that user-supplied values are properly bound as parameters rather than concatenated into SQL strings.

For detailed patch information, refer to the GitHub Commit and the GitHub Security Advisory GHSA-x3hw-rwrg-v25h.

Workarounds

• Implement network segmentation to restrict access to OpenEMR installations from untrusted networks
• Apply strict role-based access controls to limit the number of users with access to the Immunization module
• Deploy a Web Application Firewall (WAF) with SQL injection detection rules as a compensating control
• Consider temporarily disabling the Immunization module if it is not critical to operations until patching is complete

# Example: Restrict access to OpenEMR at the network level
# Add firewall rules to limit access to trusted IP ranges only
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP