CVE-2025-9705 is a SQL Injection vulnerability identified in version 1.0 of the SourceCodester Water Billing System, specifically within an unspecified function in the /paybill.php file. The vulnerability arises from improper sanitization or validation of the 'ID' parameter, allowing an attacker to manipulate this input to inject arbitrary SQL commands. This flaw enables remote attackers to execute unauthorized SQL queries on the backend database without requiring authentication or user interaction. The vulnerability has a CVSS 4.0 base score of 6.9, indicating a medium severity level. The vector metrics show that the attack can be performed remotely (AV:N), with low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The impact on confidentiality, integrity, and availability is rated as low to medium (VC:L, VI:L, VA:L), suggesting that while the attacker can potentially read or modify some data, the overall system compromise may be limited. The exploit code has been publicly disclosed, increasing the risk of exploitation, although no confirmed active exploitation in the wild has been reported yet. The vulnerability affects only version 1.0 of the product, which is a specialized water billing system likely used by municipal or utility organizations to manage billing and payments. Given the nature of the system, exploitation could lead to unauthorized access to billing records, manipulation of payment data, or disruption of billing services.

For European organizations, particularly municipal water utilities and local government bodies using the SourceCodester Water Billing System 1.0, this vulnerability poses a tangible risk. Exploitation could lead to unauthorized disclosure of customer billing information, financial data manipulation, and potential service disruption. This could undermine public trust, lead to financial losses, and cause regulatory compliance issues under GDPR due to exposure of personal data. Additionally, altered billing records could result in revenue loss or disputes with customers. The remote and unauthenticated nature of the exploit increases the attack surface, especially if the billing system is accessible over the internet or poorly segmented within internal networks. Although the severity is medium, the criticality of utility services means even moderate disruptions can have outsized impacts on communities and local governance.

To mitigate this vulnerability, affected organizations should prioritize upgrading or patching the SourceCodester Water Billing System to a version where this issue is resolved; however, no patch links are currently available, so contacting the vendor for a fix or guidance is essential. In the interim, organizations should implement strict input validation and parameterized queries or prepared statements in the /paybill.php script to prevent SQL injection. Network-level controls such as web application firewalls (WAFs) should be deployed and configured to detect and block SQL injection attempts targeting the 'ID' parameter. Access to the billing system should be restricted to trusted internal networks or VPNs, minimizing exposure to the internet. Regular security audits and code reviews should be conducted to identify similar vulnerabilities. Monitoring and logging of database queries and web application access can help detect exploitation attempts early. Finally, organizations should educate their IT staff about this vulnerability and ensure incident response plans include scenarios involving billing system compromise.