CVE-2026-25047 is a prototype pollution vulnerability classified under CWE-1321, found in the deepHas npm package maintained by sharpred. deepHas is a utility that tests for the existence of nested object keys in JavaScript objects. In versions prior to 1.0.8, an attacker can exploit improper handling of object prototype attributes to inject or modify properties on the global Object prototype. This manipulation can lead to unexpected behavior across the application, as many JavaScript operations rely on prototype inheritance. The vulnerability does not require any privileges or user interaction, making it highly accessible to remote attackers. The CVSS 4.0 score of 9.4 reflects the critical nature of this flaw, with high impact on confidentiality, integrity, and availability, and low attack complexity. Although no public exploits have been reported yet, the vulnerability's nature means it could be leveraged for privilege escalation, data tampering, or denial of service by corrupting application logic or security controls. The issue was addressed in version 1.0.8 of deepHas, which properly controls prototype modifications to prevent pollution attacks.

For European organizations, the impact of this vulnerability can be severe, especially for those relying on Node.js applications that incorporate the deepHas package or its dependencies. Prototype pollution can lead to widespread application instability, unauthorized data access, or privilege escalation, potentially compromising sensitive information or disrupting critical services. Industries such as finance, healthcare, and government, which handle sensitive data and require high availability, are particularly at risk. The vulnerability could also be exploited to bypass security controls or inject malicious code, increasing the risk of further compromise. Given the interconnected nature of modern software supply chains, even organizations not directly using deepHas might be indirectly affected through transitive dependencies. The lack of required authentication and user interaction further increases the threat surface, enabling attackers to exploit vulnerable systems remotely with relative ease.

Immediate mitigation involves upgrading all instances of the deepHas package to version 1.0.8 or later, where the vulnerability is fixed. Organizations should perform a thorough dependency audit using tools like npm audit or Snyk to identify and remediate vulnerable versions in their software supply chain, including transitive dependencies. Implement runtime protections such as input validation and sandboxing to limit the impact of prototype pollution. Employ static and dynamic code analysis to detect unsafe object manipulations. Monitor application logs and behavior for anomalies indicative of prototype pollution exploitation, such as unexpected property changes or crashes. Educate development teams on secure coding practices related to prototype handling in JavaScript. Finally, integrate vulnerability management processes that prioritize patching of critical dependencies and maintain up-to-date software inventories.