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 PostgreSQL message decoder reads the 4-byte message length field from the PostgreSQL wire protocol without any maximum validation. A malicious, compromised, or man-in-the-middle PostgreSQL server can send a message header with the length field set to an extremely large value (up to Integer.MAXVALUE), causing the decoder to accumulate subsequent TCP data into a composite buffer without bound, leading to unbounded memory allocation on the client and an out-of-memory crash. This occurs before authentication completes.

The impacted component is io.vertx:vertx-pg-client.

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.