CVE-2025-40711 is a critical SQL injection vulnerability identified in the Quiter Gateway product, specifically versions prior to 4.7.0. Quiter Gateway is a Java WAR application running on Apache Tomcat, commonly used for handling electronic invoicing processes. The vulnerability arises due to improper neutralization of special elements in SQL commands (CWE-89), specifically through the id_concesion parameter in the endpoint /<Client>FacturaE/VerFacturaPDF. This flaw allows an unauthenticated attacker to perform unauthorized database operations including retrieval, creation, modification, and deletion of data. The vulnerability is remotely exploitable over the network without requiring any privileges or user interaction, as indicated by the CVSS 4.0 vector (AV:N/AC:L/PR:N/UI:N). The impact on confidentiality, integrity, and availability is high, given the attacker can manipulate backend databases arbitrarily. Although no known exploits are currently observed in the wild, the critical CVSS score of 9.3 underscores the urgency for remediation. The lack of available patches at the time of publication further increases risk for affected deployments. The vulnerability affects all versions prior to 4.7.0, and the attack vector targets a web-accessible invoice PDF retrieval endpoint, which is likely exposed in many enterprise environments using Quiter Gateway for electronic invoicing workflows.

For European organizations, this vulnerability poses a significant risk due to the widespread adoption of electronic invoicing systems compliant with EU regulations such as FacturaE in Spain and similar e-invoicing mandates across the EU. Exploitation could lead to unauthorized access and manipulation of sensitive financial and transactional data, resulting in data breaches, financial fraud, disruption of invoicing operations, and potential regulatory non-compliance with GDPR and e-invoicing directives. The ability to delete or alter database records could disrupt business continuity and damage trust with partners and customers. Given the critical nature of invoicing systems in supply chains and financial reporting, the impact extends beyond IT to legal and financial domains. Additionally, the exposure of confidential client and transaction data could lead to reputational damage and legal penalties under European data protection laws.

Organizations should immediately assess their use of Quiter Gateway and identify affected versions prior to 4.7.0. Until an official patch is released, implement the following mitigations: 1) Employ Web Application Firewalls (WAFs) with custom rules to detect and block SQL injection attempts targeting the id_concesion parameter and related endpoints. 2) Restrict access to the /<Client>FacturaE/VerFacturaPDF endpoint via network segmentation and IP whitelisting to trusted internal or partner networks only. 3) Conduct thorough input validation and sanitization at the application layer, ensuring that all parameters passed to SQL queries are properly parameterized or use prepared statements. 4) Monitor logs for unusual database queries or errors indicative of injection attempts. 5) Plan for rapid deployment of the official patch once available and test it in staging environments prior to production rollout. 6) Review database user permissions to enforce the principle of least privilege, limiting the application's database user to only necessary operations. 7) Educate development and security teams about secure coding practices to prevent similar vulnerabilities in future releases.