A connection pool is a shared set of reusable network connections kept open so applications can send requests without creating a new connection every time. This reduces handshake overhead, lowers latency, and improves throughput for busy services such as payment APIs, databases, and internal microservices.
In cyber security, connection pools matter because they are a shared capacity limit. If a pool is exhausted, new requests may queue, time out, or fail even when the target service is otherwise healthy. Attackers and traffic spikes can exploit this by causing bursts of requests, forcing retries, or keeping connections busy long enough to starve legitimate users. Defenders reduce this risk by tuning pool size, setting timeouts, isolating critical paths, and using backpressure or circuit breakers so one overloaded component does not collapse the whole transaction flow.