Logical decoding is a PostgreSQL feature that converts committed database changes into a stream that other systems can consume. Instead of exposing raw storage pages, it emits logical change events such as inserts, updates, and deletes. Those events are formatted by output plugins, which are loaded as shared libraries. That makes logical decoding powerful for replication, analytics pipelines, and change-data-capture tools.
In cyber security, the same flexibility can become dangerous. If an attacker can reach a logical decoding path or influence which plugin is loaded, they may turn a data-streaming feature into a code-loading primitive. Defenders should treat output plugins as executable code, not just configuration, and tightly control the REPLICATION privilege, allowed plugins, and library search paths. Patching vulnerable PostgreSQL releases and disabling unused replication features reduces the attack surface.