CVE-2026-37602: Patient Appointment Scheduler SQLi Flaw

CVE-2026-37602 Overview

SourceCodester Patient Appointment Scheduler System v1.0 contains a SQL Injection vulnerability in the file /scheduler/admin/user/manage_user.php. This web application vulnerability allows authenticated attackers with high privileges to inject malicious SQL queries through the affected endpoint, potentially enabling unauthorized access to sensitive patient and appointment data stored in the underlying database.

Critical Impact

SQL Injection in healthcare appointment scheduling system could expose protected health information (PHI) and patient records to unauthorized disclosure.

Affected Products

• SourceCodester Patient Appointment Scheduler System v1.0
• /scheduler/admin/user/manage_user.php endpoint

Discovery Timeline

• 2026-04-14 - CVE-2026-37602 published to NVD
• 2026-04-14 - Last updated in NVD database

Technical Details for CVE-2026-37602

Vulnerability Analysis

This SQL Injection vulnerability (CWE-89) exists in the user management functionality of the Patient Appointment Scheduler System. The vulnerable endpoint /scheduler/admin/user/manage_user.php fails to properly sanitize user-supplied input before incorporating it into SQL queries executed against the backend database.

The attack requires network access and high-level privileges (administrator context), meaning the attacker must first authenticate to the administrative interface. While the scope is unchanged and only confidentiality is impacted at a low level, the nature of SQL Injection means that additional data exfiltration or manipulation could be possible depending on database permissions and configuration.

Healthcare scheduling systems typically store sensitive information including patient names, contact details, medical appointment history, and potentially insurance information, making this vulnerability particularly concerning in terms of regulatory compliance (HIPAA).

Root Cause

The root cause is improper input validation in the manage_user.php file where user-controlled parameters are concatenated directly into SQL queries without proper sanitization, parameterization, or use of prepared statements. This classic SQL Injection pattern allows attackers to manipulate the query logic by injecting SQL syntax through form fields or URL parameters.

Attack Vector

The vulnerability is exploitable over the network through the administrative web interface. An attacker with valid administrative credentials can craft malicious input containing SQL syntax to manipulate database queries. The attack could involve:

1. Accessing the /scheduler/admin/user/manage_user.php endpoint with administrative credentials
2. Injecting SQL payloads through vulnerable parameters in the user management form
3. Extracting database contents through UNION-based, error-based, or blind SQL injection techniques

For technical details on the SQL Injection vulnerability, refer to the GitHub SQL Injection Report.

Detection Methods for CVE-2026-37602

Indicators of Compromise

• Unusual SQL error messages in application or web server logs from the /scheduler/admin/user/manage_user.php endpoint
• Database query logs showing malformed or suspicious queries with SQL keywords in user input fields
• Anomalous data access patterns from administrative accounts, particularly bulk data retrieval
• Failed login attempts followed by successful authentication with subsequent data exfiltration activity

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect common SQL injection patterns in requests to the Patient Appointment Scheduler
• Monitor web server access logs for requests to manage_user.php containing suspicious characters such as single quotes, semicolons, UNION keywords, or comment sequences
• Deploy database activity monitoring to alert on unusual query patterns or large result sets from the scheduler database
• Utilize SIEM correlation rules to identify SQL injection attack signatures targeting healthcare application endpoints

Monitoring Recommendations

• Enable verbose logging on the web application and database servers to capture full request parameters
• Configure alerts for HTTP 500 errors from the scheduler application that may indicate SQL syntax errors from injection attempts
• Monitor administrative user sessions for anomalous behavior patterns such as accessing user management functions outside normal hours
• Review database audit logs regularly for signs of unauthorized data access or schema enumeration

How to Mitigate CVE-2026-37602

Immediate Actions Required

• Restrict network access to the administrative interface (/scheduler/admin/) to trusted IP addresses only
• Implement additional authentication controls such as multi-factor authentication for administrative accounts
• Deploy a Web Application Firewall with SQL injection protection rules in front of the Patient Appointment Scheduler System
• Audit administrative user accounts and remove any unnecessary privileged access
• Consider taking the vulnerable endpoint offline until a patch is available

Patch Information

No official vendor patch is currently available for this vulnerability. As this is a SourceCodester application, users should monitor the vendor's website and the original GitHub SQL Injection Report for updates and potential fixes.

For organizations with development capabilities, the vulnerability can be remediated by modifying the /scheduler/admin/user/manage_user.php file to use parameterized queries or prepared statements instead of string concatenation for SQL query construction.

Workarounds

• Implement network segmentation to restrict access to the administrative interface from untrusted networks
• Deploy a reverse proxy or WAF with SQL injection filtering capabilities to inspect and sanitize requests to the vulnerable endpoint
• If source code access is available, manually implement input validation and parameterized queries in the affected file
• Limit database user permissions to the minimum required for application functionality, reducing the impact of successful SQL injection

# Example: Restrict access to admin directory using Apache .htaccess
# Place in /scheduler/admin/.htaccess
<RequireAll>
    Require ip 192.168.1.0/24
    Require ip 10.0.0.0/8
</RequireAll>

# Deny access to manage_user.php from all external sources
<Files "manage_user.php">
    Require ip 192.168.1.0/24
</Files>