CVE-2025-6449 is a critical SQL Injection vulnerability identified in version 1.0 of the Simple Online Hotel Reservation System developed by code-projects. The vulnerability exists in the /admin/checkout_query.php file, specifically through the manipulation of the 'transaction_id' parameter. An attacker can remotely exploit this flaw without requiring any authentication or user interaction. By injecting malicious SQL code into the 'transaction_id' parameter, the attacker can manipulate backend database queries, potentially leading to unauthorized data access, data modification, or deletion. The vulnerability is classified with a CVSS 4.0 base score of 6.9, indicating a medium severity level, primarily due to limited impact on confidentiality, integrity, and availability (all rated low), but with ease of exploitation (no privileges or user interaction needed) and remote network attack vector. Although no public exploits are currently known in the wild, the exploit details have been disclosed publicly, increasing the risk of exploitation. The affected product is a web-based hotel reservation system, which is likely used by small to medium hospitality businesses to manage bookings and transactions. The lack of available patches or vendor advisories at this time increases the urgency for organizations to implement mitigations.

For European organizations, particularly those in the hospitality sector using the Simple Online Hotel Reservation System version 1.0, this vulnerability poses a significant risk. Successful exploitation could lead to unauthorized access to sensitive customer data, including booking details and payment transaction information, potentially violating GDPR regulations and resulting in financial and reputational damage. Data integrity could also be compromised, affecting reservation accuracy and operational reliability. Although the vulnerability does not directly impact system availability, manipulation of database queries could disrupt booking processes, leading to service interruptions. The remote and unauthenticated nature of the exploit increases the attack surface, especially for publicly accessible administrative interfaces. Given the hospitality industry's importance in Europe, especially in countries with high tourism volumes, the vulnerability could have broader economic implications if exploited at scale.

1. Immediate mitigation should include restricting access to the /admin/checkout_query.php endpoint via network-level controls such as IP whitelisting or VPN access to limit exposure to trusted personnel only. 2. Implement Web Application Firewall (WAF) rules specifically designed to detect and block SQL injection patterns targeting the 'transaction_id' parameter. 3. Conduct a thorough code review and apply input validation and parameterized queries (prepared statements) to sanitize all inputs, especially the 'transaction_id' parameter, to prevent SQL injection. 4. If possible, isolate the affected system from the internet or place it behind additional authentication layers until a vendor patch or update is available. 5. Monitor logs for unusual database query patterns or repeated failed attempts to access the vulnerable parameter. 6. Engage with the vendor or community to obtain or develop patches and update the system promptly once available. 7. Educate administrative users about the risks of using default or weak credentials and enforce strong authentication mechanisms to reduce the risk of lateral movement post-exploitation.