Junglewise Threat Intelligence

CVE-2026-51221: EIPStackGroup OpENer buffer overflow in Get_Attribute_List

CVE-2026-51221 · Severity: info · CVSS 7.5 · Published 2026-06-29

Technologies: EIPStackGroup OpENer. Vendors: EIPStackGroup.

Executive brief

OpENer is an open-source software stack used by industrial devices to communicate over the EtherNet/IP protocol. A security flaw allows a remote attacker to crash the software by sending a specially crafted network packet. This could lead to a denial-of-service (DoS) condition, disrupting industrial operations or communication between automated devices.

Technical details

A buffer overflow exists in the Get_Attribute_List function within EIPStackGroup OpENer (specifically commit 76b95cf). The vulnerability is triggered when the stack processes a malformed Common Packet Format (CPF) packet with an inconsistent item count. During response re-assembly in EncodeMessageRouterResponseData, the software fails to validate destination capacity before copying an oversized Message Router response into the ENIPMessage buffer. This results in an out-of-bounds write that corrupts the adjacent current_message_position pointer, leading to a segmentation fault and denial of service when the corrupted pointer is later dereferenced in AddIntToMessage. The attack is reachable over the network without authentication.

Affected products

  • EIPStackGroup OpENer commit 76b95cf951a18d0e8481833168ab8c6943ce7c96

Timeline

  • 2026-06-29: disclosed: Vulnerability reported via GitHub issues and published to NVD.

References

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