CVE-2026-51537 [CRITICAL] – EIPStackGroup OpENer 2.3.0 (commit 76b95cf) has an out-of-bounds read issue in Connection

EIPStackGroup OpENer 2.3.0 (commit 76b95cf) has an out-of-bounds read issue in Connection Manager handling of ForwardOpen requests when processing short malformed packets. An attacker can send a valid ENIP outer frame carrying a malformed CIP ForwardOpen/LargeForwardOpen request, causing the parser to continue reading fields even when request data is insufficient. This issue is remotely triggerable via network traffic and does not require authentication.