An out-of-bounds read vulnerability exists in EIPStackGroup OpENer v2.3 and master up to commit 76b95cf in the EtherNet/IP TCP SendRRData Common Packet Format parser. The issue occurs in CreateCommonPacketFormatStructure() when it parses recognized optional socket address information items of type 0x8000 or 0x8001 without first validating that the remaining CPF buffer contains the complete fixed sockaddr structure. This allows a remote attacker to cause a denial of service.