Nest is a framework for building scalable Node.js server-side applications. Prior to 11.2.4 and 12.0.2, a single message with a deeply nested object in its pattern can terminate a NestJS microservice using the TCP or RabbitMQ transport. ServerTCP#handleMessage and ServerRMQ#handleMessage pass a client-controlled non-string pattern to JSON.stringify to derive the handler lookup key; sufficiently deep nesting throws RangeError: Maximum call stack size exceeded, and the unhandled promise rejection terminates Node.js under its default behavior. An attacker who can reach the TCP port or publish to the consumed RabbitMQ queue or exchange can crash the service on demand; other transports are not affected because their patterns arrive as strings. This issue is fixed in versions 11.2.4 and 12.0.2.