CVE-2025-6394 is a SQL Injection vulnerability identified in version 1.0 of the code-projects Simple Online Hotel Reservation System, specifically within the /add_reserve.php file. The vulnerability arises from improper sanitization or validation of the 'firstname' parameter, allowing an attacker to inject malicious SQL code remotely without requiring authentication or user interaction. This flaw enables attackers to manipulate backend SQL queries, potentially leading to unauthorized data access, data modification, or deletion. The vulnerability is rated with a CVSS 4.0 score of 6.9 (medium severity), reflecting its network attack vector, low attack complexity, no privileges or user interaction needed, and limited impact on confidentiality, integrity, and availability. Although the exploit has been publicly disclosed, there are no known active exploits in the wild at this time. The vulnerability may also affect other parameters beyond 'firstname', indicating a broader input validation issue in the reservation system. The Simple Online Hotel Reservation System is typically used by small to medium-sized hospitality businesses to manage bookings online, making it a critical component for operational continuity and customer data protection.

For European organizations, particularly those in the hospitality sector using the affected Simple Online Hotel Reservation System version 1.0, this vulnerability poses significant risks. Exploitation could lead to unauthorized disclosure of sensitive customer information, including personal details submitted during reservations. Attackers might also alter or delete reservation data, disrupting business operations and causing reputational damage. Given the system's role in managing bookings, availability impacts could result in lost revenue and customer trust. The remote and unauthenticated nature of the attack vector increases the risk of widespread exploitation, especially if patches or mitigations are not promptly applied. Additionally, compromised systems could serve as pivot points for further attacks within organizational networks. The medium severity rating suggests that while the impact is serious, it may not lead to full system compromise or widespread data breaches without additional vulnerabilities or misconfigurations.

1. Immediate application of input validation and parameterized queries (prepared statements) within the /add_reserve.php script to sanitize all user inputs, especially the 'firstname' parameter and any other parameters that interact with SQL queries. 2. Conduct a comprehensive code audit of the entire application to identify and remediate other potential injection points. 3. If available, upgrade to a patched version of the Simple Online Hotel Reservation System or apply vendor-provided patches promptly. 4. Implement Web Application Firewalls (WAFs) with custom rules to detect and block SQL injection attempts targeting the reservation system endpoints. 5. Monitor application logs for unusual query patterns or repeated failed attempts to exploit SQL injection. 6. Restrict database user permissions to the minimum necessary for application functionality to limit the impact of a successful injection. 7. Educate development and IT teams on secure coding practices and the importance of input validation. 8. For organizations unable to immediately patch, consider isolating the affected system from external networks or limiting access to trusted IP addresses until remediation is complete.