CVE-2026-75349

An out-of-bounds read vulnerability was found in OpENer 2.3.0 (commit 76b95cf) during CIP message parsing. An attacker can send a valid ENIP SendRRData frame with a very short CIP payload where the path_size field claims more path words than available. Because the parser trusts the attacker-controlled path_size and continues decoding path segments without a remaining-length boundary check, it reads beyond the end of the stack receive buffer.

OpENer 2.3.0 (master branch up to commit 76b95cf) is vulnerable to a severe memory corruption issue caused by an integer underflow in the processing of connected explicit messages (SendUnitData).

An incorrect access control vulnerability was found in OpENer 2.3.0 (commit 76b95cf) during encapsulation session handling. The server only checks if a session handle exists in the global list but does not verify if it belongs to the specific TCP connection making the request. This allows an attacker to hijack another client's session and bypass access controls.

In OpENer 2.3.0 (commit 76b95cf) when parsing CIP packets, the length parameter is inconsistently typed across the call stack. An int length is passed to a function expecting EipInt16, allowing crafted packets to cause overflow or negative values. This bypasses bounds checks and leads to a stack buffer overflow in DecodePaddedEPath.

OpENer v2.3/commit 76b95cf contains an out-of-bounds read in the server-side EtherNet/IP ForwardOpen connection-path parser. This allows a remote attacker to cause a denial of service.

OpENer v2.3/commit 76b95cf contains an integer underflow in the server-side EtherNet/IP ForwardOpen connection-path parser. This allows a remote attacker to cause a denial of service.

OpENer v2.3 (commit 76b95cf) contains an out-of-bounds read in the server-side EtherNet/IP ForwardOpen connection-path parser. This allows a remote attacker to cause a denial of service.

EIPStackGroup OpENer v2.3 / master commit 76b95cf contains a buffer overflow in the GetAttributeList() implementation for the EtherNet/IP Get_Attribute_List service. This allows a remote attacker to cause a denial of service.

EIPStackGroup OpENer v2.3 and master up to commit 76b95cf contain an expired pointer dereference vulnerability in the EtherNet/IP Common Packet Format (CPF) handling logic. This allows a remote attacker to cause a denial of service.

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 parsing optional socket address items of type 0x8000 or 0x8001 without validating that the remaining CPF buffer contains the complete fixed sockaddr structure, allowing a remote attacker to cause a denial of service.