In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the binary array decoder in vertx-pg-client (DataTypeCodec.binaryDecodeArray) allocates a Java array sized by a server-declared 32-bit dimension count with no upper bound. A malicious or compromised PostgreSQL server, or an on-path attacker intercepting an unencrypted connection, can send a crafted DataRow message with an excessively large array dimension value, causing the client to attempt a multi-gigabyte heap allocation and crash with an OutOfMemoryError.
The impacted component is io.vertx:vertx-pg-client.