CVE-2025-4817 is a critical SQL Injection vulnerability identified in Sourcecodester Doctor's Appointment System version 1.0. The vulnerability exists in the /admin/delete-appointment.php file, specifically in the GET parameter handler for the 'ID' argument. An attacker can remotely manipulate this parameter to inject malicious SQL code into the backend database queries. This injection flaw allows an unauthenticated attacker to execute arbitrary SQL commands without any user interaction or privileges, potentially leading to unauthorized data access, data modification, or deletion. The vulnerability is exploitable over the network without authentication, increasing the attack surface significantly. Although the CVSS v4.0 score is 6.9 (medium severity), the nature of SQL injection vulnerabilities typically poses a high risk due to the potential for data breaches and system compromise. No patches or fixes have been linked yet, and while there are no known exploits in the wild, public disclosure increases the risk of exploitation by threat actors. The vulnerability affects only version 1.0 of the product, which is a web-based appointment management system used in healthcare settings to schedule and manage doctor appointments. The lack of secure coding practices in input validation and parameter handling is the root cause of this issue.

For European organizations, particularly healthcare providers using Sourcecodester Doctor's Appointment System 1.0, this vulnerability could lead to severe consequences. Exploitation could result in unauthorized access to sensitive patient data, including personal health information (PHI), violating GDPR and other data protection regulations. Data integrity could be compromised, leading to incorrect appointment records or deletion of critical scheduling data, disrupting healthcare services. Availability of the appointment system could also be affected if attackers execute destructive SQL commands, causing denial of service. The reputational damage and regulatory penalties from such data breaches could be substantial. Given the critical nature of healthcare services and the sensitivity of patient data, this vulnerability represents a significant risk to European healthcare institutions relying on this software.

Organizations should immediately audit their use of Sourcecodester Doctor's Appointment System version 1.0 and plan to upgrade or patch the software once a fix is available. In the interim, implementing web application firewall (WAF) rules to detect and block SQL injection attempts targeting the 'ID' parameter in /admin/delete-appointment.php can reduce risk. Input validation and parameterized queries should be enforced in the application code to prevent injection. Restricting access to the admin interface by IP whitelisting or VPN can limit exposure. Regular security assessments and code reviews focusing on input handling should be conducted. Monitoring logs for suspicious query patterns and failed injection attempts can provide early detection. If possible, isolate the appointment system from other critical infrastructure to contain potential breaches.