The vulnerability is an out‑of‑bounds read in the server‑side EtherNet/IP ForwardOpen connection‑path parser of OpENer v2.3. A remote attacker can send a specially crafted ForwardOpen request that causes the parser to read beyond the input buffer, resulting in a crash or hang that leaves the server unable to accept further connections. The flaw does not provide remote code execution or data disclosure; it solely impacts availability.

Devices and services that run OpENer v2.3 and have theNet/IP ForwardOpen functionality enabled are affected. This includes industrial controllers, gateways, and other Ethernet/IP devices that incorporate the OpENer stack. No manufacturer or product names are listed in the data, but any deployment of OpENer v2.3 that uses the ForwardOpen command is potentially vulnerable.

The CVSS score is 7.5, and the EPSS score is not available; the vulnerability is not listed in CISA’s KEV catalog. The flaw can be triggered from any network reachable over EtherNet/IP because traffic travels over standard Ethernet or TCP connections. An attacker would need to craft a malformed connection path in a ForwardOpen request; based on the description, it is inferred that no authentication is required to reach the vulnerable parser. Because the effect is a service crash, the risk is primarily availability disruption with no compromise of data or risk to other system components.