CVE-2026-5551: Hotel Reservation System SQLi Vulnerability

CVE-2026-5551 Overview

A SQL Injection vulnerability has been discovered in itsourcecode Free Hotel Reservation System version 1.0. This security flaw affects the /hotel/admin/login.php file within the Parameter Handler component. By manipulating the email argument, an attacker can inject arbitrary SQL commands. The attack can be launched remotely without authentication, and the exploit has been publicly released, increasing the risk of active exploitation.

Critical Impact

This SQL Injection vulnerability allows remote attackers to manipulate database queries through the email parameter in the admin login page, potentially leading to unauthorized data access, data modification, or complete database compromise.

Affected Products

• itsourcecode Free Hotel Reservation System 1.0
• /hotel/admin/login.php - Parameter Handler component

Discovery Timeline

• 2026-04-05 - CVE-2026-5551 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-5551

Vulnerability Analysis

This vulnerability is classified under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component, also known as Injection). The vulnerable code fails to properly sanitize the email parameter before incorporating it into SQL queries, creating a classic SQL Injection attack surface.

The network-accessible nature of this vulnerability means attackers can exploit it remotely without requiring any prior authentication or user interaction. The admin login functionality at /hotel/admin/login.php processes user-supplied email input directly in database queries, allowing attackers to craft malicious input that alters the intended SQL logic.

When exploited, this flaw can enable attackers to bypass authentication mechanisms, extract sensitive data from the database, modify or delete records, and potentially escalate to broader system compromise depending on database permissions and configuration.

Root Cause

The root cause of this vulnerability is improper input validation and the absence of parameterized queries (prepared statements) in the login authentication mechanism. The application directly concatenates user-supplied input from the email parameter into SQL queries without proper sanitization or escaping, allowing special characters and SQL syntax to be interpreted as executable code rather than data.

Attack Vector

The attack is network-based and targets the admin login endpoint. An attacker can send specially crafted HTTP requests to /hotel/admin/login.php with malicious SQL payload in the email parameter. Since the exploit has been publicly released, attackers can leverage existing proof-of-concept code to conduct authentication bypass attacks or data extraction operations.

The vulnerability can be exploited through standard HTTP POST requests to the login form, making it accessible to any attacker with network access to the application. No special tools or authentication are required to initiate an attack.

Technical details and proof-of-concept information can be found in the GitHub CVE Issue and VulDB Vulnerability #355315.

Detection Methods for CVE-2026-5551

Indicators of Compromise

• Unusual SQL syntax or special characters (e.g., single quotes, semicolons, OR 1=1, UNION SELECT) in web server access logs for /hotel/admin/login.php
• Failed login attempts with anomalous email parameter values containing SQL keywords
• Database query errors or unexpected query patterns in database logs
• Unauthorized access to admin functionality or data exfiltration from the hotel reservation database

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block SQL injection patterns in the email parameter
• Monitor web server logs for requests to /hotel/admin/login.php containing SQL injection signatures
• Enable database query logging and alert on queries with unusual syntax or unauthorized data access patterns
• Deploy intrusion detection systems (IDS) with SQL injection detection signatures

Monitoring Recommendations

• Set up real-time alerting for any SQL errors generated by the hotel reservation system database
• Monitor authentication logs for successful logins following multiple failed attempts with malformed input
• Track database access patterns for anomalous bulk data queries or schema enumeration activities

How to Mitigate CVE-2026-5551

Immediate Actions Required

• Restrict access to the admin login page (/hotel/admin/login.php) to trusted IP addresses using network-level controls
• Implement a Web Application Firewall (WAF) with SQL injection protection rules
• Review application logs for signs of exploitation attempts
• Consider taking the application offline if active exploitation is suspected

Patch Information

No official patch information is currently available from the vendor. Organizations using itsourcecode Free Hotel Reservation System 1.0 should monitor the ITSourceCode website for security updates.

In the absence of a vendor patch, organizations should implement code-level fixes by modifying the application to use parameterized queries (prepared statements) for all database interactions in the login functionality.

Workarounds

• Implement input validation to reject email parameters containing SQL special characters or keywords
• Use prepared statements with parameterized queries in the login.php file to prevent SQL injection
• Deploy a reverse proxy or WAF to filter malicious requests before they reach the application
• Restrict database user permissions to limit the impact of successful SQL injection attacks

# Example: Apache .htaccess configuration to restrict admin access by IP
<Files "login.php">
    Order Deny,Allow
    Deny from all
    Allow from 192.168.1.0/24
    Allow from 10.0.0.0/8
</Files>