EIPStackGroup OpENer contains a buffer overflow in the GetAttributeList() implementation for the EtherNet/IP Get_Attribute_List service. A crafted request targets the vulnerable master commit 76b95cf, causing the overflow, crashing the process, and resulting in a denial of service. The overflow does not enable code execution; it only disrupts the EtherNet/IP functionality.

All installations of OpENer v2.3 and earlier that have not applied the latest security patch are affected. The issue exists in the master branch at commit 76b95cf, so any build based on or before that commit remains vulnerable. Devices utilizing the OpENer stack in industrial control environments are at risk if they expose the Get_Attribute_List service.

The CVSS score of 7.5 indicates a high impact and medium‑to‑high exploitability. An EPSS score of less than 1% and absence from CISA KEV suggest exploitation is currently uncommon, yet the vulnerability is trivially exploitable from any host that can reach the EtherNet/IP port. No authentication is required, so an attacker with network connectivity can repeatedly trigger the overflow and disrupt service.