An issue in the NetStaX EtherNet/IP Stack prior to v5.6.1 could allow a large Class 3 explicit-message request to exceed the application-side receive buffer without generating an error or warning. The result could be memory corruption, a device crash, or a potential remote attack vector without the originating device receiving a CIP error indicating that the request could not be processed.
NetStaX v5.6.1 addresses this issue with multiple layers of protection, including a compile-time assertion, a runtime payload-size check, and clearer documentation of the relationships between packet and buffer-size constants.
For more information, see the Pyramid Solutions blog post "NetStaX v5.6.1: Protecting Against Silent Buffer Overflow in Ethernet/IP Stack Explicit Messages".