Node.js Web Application does not handle uncaughtException
Description
Node.js applications emit an uncaughtException event when a JavaScript exception propagates without being caught by any error handler. Without proper handling, the application terminates immediately with exit code 1, potentially leaving the system in an inconsistent state. While Node.js provides a mechanism to listen for this event, proper handling requires careful implementation to ensure application stability and security.
Remediation
Implement an uncaughtException handler that logs the error, performs necessary synchronous cleanup, and explicitly terminates the process. Important: Do not attempt to resume normal operation after an uncaught exception, as the application state may be corrupted. Instead, rely on a process manager (such as PM2, systemd, or Docker restart policies) to automatically restart the application.
Example implementation:
process.on('uncaughtException', (error) => {
// Log the error with full stack trace
console.error('Uncaught Exception:', error);
// Perform synchronous cleanup only (close file handles, etc.)
// Do NOT perform async operations here
// Exit the process - let the process manager restart it
process.exit(1);
});
Additionally, implement proper error handling throughout your application using try-catch blocks and promise rejection handlers to prevent exceptions from becoming uncaught in the first place. Deploy your application with a process manager configured to automatically restart on failure.