CVE-2025-59437 is a Server-Side Request Forgery (SSRF) vulnerability identified in the 'ip' package (also known as 'node-ip') maintained by fedorindutny, specifically affecting versions through 2.0.1 available on NPM. The vulnerability arises because the package incorrectly categorizes the IP address value 0 (interpreted as 0.0.0.0) as globally routable via its isPublic function. This misclassification stems from an incomplete fix for a previous vulnerability, CVE-2024-29415. In many environments, connection attempts to 0 or 0.0.0.0 are blocked with errors like net::ERR_ADDRESS_INVALID; however, in certain application versions and operating systems, these attempts are treated as connections to the localhost address 127.0.0.1. This behavior can be exploited by attackers to induce the server to make unintended requests to internal services or localhost endpoints, potentially bypassing network restrictions or firewall rules. The vulnerability does not require user interaction or privileges but has a high attack complexity due to environment-specific behavior. The CVSS v3.1 base score is 3.2, indicating a low severity primarily due to limited impact on confidentiality and availability, with integrity being the main concern. No known exploits are currently reported in the wild, and no patches have been linked yet, suggesting that mitigation relies on awareness and cautious use of the affected package versions.

For European organizations, the impact of this SSRF vulnerability depends largely on the deployment of the 'ip' package within their software stacks, particularly in Node.js applications that process or validate IP addresses. Exploitation could allow attackers to perform unauthorized internal network scans or access internal services that are otherwise protected, potentially leading to information disclosure or indirect integrity compromises. While the vulnerability itself is low severity, it could serve as a pivot point in multi-stage attacks targeting internal infrastructure or sensitive services, especially in sectors with critical internal networks such as finance, healthcare, and government. Given the complexity and environment-specific nature of the vulnerability, exploitation may be limited but should not be disregarded. European organizations with Node.js environments that incorporate this package should be vigilant, as internal network architectures and regulatory requirements (e.g., GDPR) heighten the importance of preventing unauthorized internal access.

1. Immediate auditing of all Node.js applications and dependencies to identify usage of the 'ip' package (node-ip) versions up to 2.0.1. 2. Where possible, upgrade to a patched or newer version of the package once available from the vendor or maintainers. 3. Implement strict input validation and sanitization for IP address inputs, ensuring that special IP addresses like 0.0.0.0 and localhost are handled securely and not treated as publicly routable. 4. Employ network segmentation and firewall rules to restrict server-side requests from application servers to only necessary internal services, minimizing the attack surface for SSRF. 5. Monitor application logs for unusual outbound requests, especially those targeting localhost or internal IP ranges, to detect potential exploitation attempts. 6. Consider using runtime application self-protection (RASP) or web application firewalls (WAFs) that can detect and block SSRF patterns. 7. Educate development teams about the risks of SSRF and the importance of proper IP address handling in code.