@Gail Badner, I'm afraid I don't know if there was a version of Hibernate that didn't suffer from this. We have had this issue for a long time, it is just that this past Black Friday, due to an overall database slowness we could easily spot it. Before, this used to happen from time to time and gradually consume the connections in the pool. It happened with certain level of frequency in applications that had shorter socket timeouts. We try to keep our Hibernate version up -to-date, and so we've been using 5.2.12 almost since it was officially released.