Prototype pollution remains a critical yet often overlooked vulnerability in Node.js applications. This analysis demonstrates how an attacker can manipulate the object prototype chain to inject properties that lead to command execution. The article walks through a real-world case, showing the step-by-step exploitation process and the impact on the host system. For developers, the key takeaway is to validate and sanitize all user inputs, especially when merging objects or parsing JSON. Using libraries like lodash with safe defaults, freezing prototypes, and applying strict CSP can significantly reduce the risk. This topic is evergreen because new frameworks and dependencies continue to introduce similar patterns. Security teams should prioritize auditing their codebase for such flaws and integrate automated scanning tools into CI/CD pipelines. Understanding the attack chain is the first step toward building more resilient Node.js services.
A practical analysis of prototype pollution vulnerabilities in Node.js that can escalate to remote command execution, with mitigation insights.