CVE-2026-4237: Hotel Reservation System SQLi Vulnerability

CVE-2026-4237 Overview

A SQL Injection vulnerability has been discovered in itsourcecode Free Hotel Reservation System 1.0. This vulnerability affects the file /hotel/admin/mod_reports/index.php, where manipulation of the Home argument can lead to SQL injection attacks. The vulnerability is remotely exploitable, and an exploit has been publicly disclosed.

Critical Impact

Remote attackers can exploit this SQL Injection vulnerability to manipulate database queries, potentially extracting sensitive guest information, modifying reservation data, or compromising the entire hotel management database.

Affected Products

• itsourcecode Free Hotel Reservation System 1.0

Discovery Timeline

• 2026-03-16 - CVE-2026-4237 published to NVD
• 2026-03-16 - Last updated in NVD database

Technical Details for CVE-2026-4237

Vulnerability Analysis

This vulnerability is classified under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), which encompasses injection vulnerabilities including SQL Injection. The flaw exists in the administrative reports module of the Free Hotel Reservation System, specifically within the index.php file located at /hotel/admin/mod_reports/.

The vulnerable application fails to properly sanitize user-supplied input in the Home parameter before incorporating it into SQL queries. This lack of input validation allows attackers to inject malicious SQL statements that are then executed by the database server.

Root Cause

The root cause of this vulnerability is improper input validation and lack of parameterized queries in the affected PHP file. The application directly concatenates user input from the Home parameter into SQL query strings without proper sanitization or use of prepared statements. This is a common vulnerability pattern in PHP applications that use legacy database interaction methods.

Attack Vector

The attack vector is network-based, allowing remote exploitation without authentication requirements. An attacker can craft malicious HTTP requests targeting the /hotel/admin/mod_reports/index.php endpoint with specially crafted values in the Home parameter. The malicious input is processed by the application and executed against the backend database, enabling attackers to:

• Extract sensitive data from the database (guest information, payment details, reservations)
• Modify or delete database records
• Potentially escalate privileges within the application
• In some configurations, execute commands on the underlying operating system

The vulnerability mechanism involves injecting SQL commands through the Home parameter. When the application processes this parameter without proper sanitization, the injected SQL code becomes part of the query executed against the database. For detailed technical analysis and proof-of-concept information, see the GitHub Issue Tracker Entry and VulDB #351179.

Detection Methods for CVE-2026-4237

Indicators of Compromise

• Unusual or malformed HTTP requests to /hotel/admin/mod_reports/index.php containing SQL syntax in the Home parameter
• Database error messages in application logs indicating SQL syntax errors or injection attempts
• Unexpected database queries or data modifications in database audit logs
• Access patterns showing repeated requests to the vulnerable endpoint with varying payloads

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect SQL injection patterns in HTTP requests targeting the affected endpoint
• Monitor application logs for SQL error messages that may indicate injection attempts
• Deploy intrusion detection systems (IDS) with signatures for common SQL injection payloads
• Use database activity monitoring to detect anomalous query patterns

Monitoring Recommendations

• Enable verbose logging on the web server for requests to /hotel/admin/mod_reports/ directory
• Configure database query logging to capture and analyze suspicious queries
• Set up alerts for failed SQL queries or unusual database access patterns
• Monitor for outbound data exfiltration attempts that may follow successful exploitation

How to Mitigate CVE-2026-4237

Immediate Actions Required

• Restrict access to the /hotel/admin/mod_reports/index.php file using network-level controls or authentication
• Implement WAF rules to block requests containing SQL injection patterns to the affected endpoint
• Review and audit all database accounts used by the application to enforce least privilege
• Consider taking the affected functionality offline until a patch is available

Patch Information

No official vendor patch has been confirmed at this time. The application is distributed through IT Source Code, and users should monitor for security updates. Given this is an open-source project, organizations should consider implementing their own fixes by modifying the source code to use prepared statements and parameterized queries.

For additional vulnerability details and tracking information, refer to VulDB #351179 and the VulDB Submission #771243.

Workarounds

• Implement input validation at the application level by modifying the PHP code to sanitize the Home parameter using mysqli_real_escape_string() or equivalent functions
• Replace dynamic SQL queries with prepared statements using PDO or MySQLi prepared statement functions
• Deploy a reverse proxy or WAF in front of the application to filter malicious requests
• Restrict network access to the admin interface to trusted IP addresses only

To implement basic input sanitization as a temporary measure, modify the affected PHP file to validate and sanitize the Home parameter before use in database queries. Additionally, restrict access to administrative functions using .htaccess rules:

# Restrict access to admin reports module
<Directory "/hotel/admin/mod_reports">
    Order Deny,Allow
    Deny from all
    Allow from 192.168.1.0/24
    # Add additional trusted IPs as needed
</Directory>