CVE-2026-5551: SQL Injection in itsourcecode Free Hotel Reservation System Login

CVE-2026-5551: SQL Injection in Free Hotel Reservation System Login Page

A SQL injection vulnerability tracked as CVE-2026-5551 has been disclosed in itsourcecode Free Hotel Reservation System 1.0, a PHP-based open-source hotel reservation management application. The flaw resides in the login page's parameter handling and is remotely exploitable, making it a risk for any deployment of this software accessible from a network.

The vulnerability was assigned a CVSS v3.1 score of 7.3 (High) and classified under CWE-89 — Improper Neutralization of Special Elements used in SQL Commands.

Vulnerability Overview

Technical Details

Affected Component

The vulnerability exists in the admin login page of the hotel reservation system. When a user submits the login form at /hotel/admin/login.php, the application accepts the email parameter and passes it directly into a SQL query without adequate sanitization or use of parameterized statements.

Exploitation Mechanism

An unauthenticated attacker who can reach the login page can inject arbitrary SQL through the email field. Common attack patterns include:

email=admin'--
email=admin' OR '1'='1
email=admin' UNION SELECT NULL,NULL,NULL--

Depending on the database configuration and the application's SQL query structure, successful exploitation could allow:

• Authentication bypass — Logging in as an administrator without valid credentials by manipulating the WHERE clause
• Credential extraction — Retrieving hashed or plaintext passwords for all accounts via UNION-based injection
• Database enumeration — Dumping table names, user data, and reservation records
• Data manipulation — Inserting, modifying, or deleting records in the backend database

Attack Flow

1. Attacker identifies an internet-accessible Free Hotel Reservation System instance

2. Attacker navigates to /hotel/admin/login.php

3. Attacker submits a crafted email value with SQL injection payload

4. Unsanitized input is executed as SQL against the backend MySQL/MariaDB database

5. Authentication logic is bypassed OR full database contents extracted

6. Attacker gains admin panel access and full control over reservation data

Affected Software Context

itsourcecode distributes free PHP web application source code for academic and learning purposes. The Free Hotel Reservation System 1.0 is a frequently downloaded project intended for PHP web development practice.

Despite the educational intent, these applications are routinely deployed in small production environments — hotels, guesthouses, or academic projects — without security hardening. CVE-2026-5551 is part of a recurring pattern of SQL injection vulnerabilities across itsourcecode PHP applications stemming from a systemic absence of input validation and parameterized queries throughout their codebase.

Remediation

Immediate Steps

No official patch has been released. Deployments of this software should implement the following mitigations:

1. Restrict admin panel access — Block /hotel/admin/ from public internet access using firewall rules, .htaccess restrictions, or network-level ACLs
2. Implement a Web Application Firewall (WAF) — Deploy ModSecurity, Cloudflare WAF, or an equivalent with SQL injection detection rules enabled
3. Parameterize all SQL queries — If maintaining a fork, replace raw string interpolation with prepared statements using PDO or MySQLi
4. Rotate all credentials — If the system has been internet-accessible, assume all stored credentials are compromised
5. Audit access logs — Review server logs for anomalous POST requests to the login endpoint

Code-Level Fix

The root cause is unsanitized parameter interpolation into SQL queries. The fix requires replacing direct parameter injection:

// Vulnerable pattern
$query = "SELECT * FROM admin WHERE email = '" . $_POST['email'] . "'";
 
// Secure pattern (PDO prepared statement)
$stmt = $pdo->prepare("SELECT * FROM admin WHERE email = ?");
$stmt->execute([$_POST['email']]);

Impact Assessment

Key Takeaways

1. CVE-2026-5551 is a CVSS 7.3 SQL injection affecting the login page of itsourcecode Free Hotel Reservation System 1.0
2. The email POST parameter is unsanitized, enabling direct SQL manipulation including authentication bypass
3. No official patch exists — access restriction and WAF deployment are the immediate mitigations
4. This continues a broad pattern of SQL injection vulnerabilities in itsourcecode PHP applications — treat any itsourcecode project as security-unreviewed before production use

Sources

• CVE-2026-5551 — NIST NVD