# CVE-2026-75351: OpENer out-of-bounds read in ForwardOpen connection-path parser

Source: https://junglewise.ai/threats/cve-2026-75351-opener-v2-3-commit-76b95cf-contains-an-out-of-bounds-read-in-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-09. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-75351 · Severity: high · CVSS 7.5 · Published 2026-10-09

OpENer is an EtherNet/IP stack used in industrial I/O adapter devices to communicate over Ethernet networks. A remote attacker can send a specially crafted EtherNet/IP packet to cause the server to read memory beyond the bounds of its receive buffer, crashing the device and causing a denial of service.

Technologies: [EIPStackGroup OpENer](https://junglewise.ai/threats/technologies/opener). Vendors: [EIPStackGroup](https://junglewise.ai/threats/vendors/eipstackgroup).

## Quick answers

**Is CVE-2026-75351 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-75351 being exploited in the wild.

**How severe is CVE-2026-75351?** High severity, with a CVSS score of 7.5, published 9 October 2026.

**Which products and versions are affected?** EIPStackGroup OpENer v2.3 and master branch up to commit 76b95cf.

**Is there a fix for CVE-2026-75351?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-75351 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-75351?** Check whether you run EIPStackGroup OpENer at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an out-of-bounds read in ParseConnectionPath() where the parser advances the message pointer by the actual segment encoding width but decrements the remaining_path counter by the decoded value size heuristic, causing desynchronization. A remote attacker can craft a ForwardOpen message with 32-bit logical class/instance/connection-point segments to trigger reading past the end of the TCP receive buffer, reliably crashing the server process.

## Affected products

- EIPStackGroup OpENer v2.3 and master branch up to commit 76b95cf

## Timeline

- 2026-05-28: disclosed
- 2026-10-09: advisory

## References

- [https://github.com/EIPStackGroup/OpENer](https://github.com/EIPStackGroup/OpENer)
- [https://github.com/EIPStackGroup/OpENer/issues/574](https://github.com/EIPStackGroup/OpENer/issues/574)

## Related threats

- [OpENer out-of-bounds read in EtherNet/IP ForwardOpen parser](https://junglewise.ai/threats/cve-2026-75353-opener-v2-3-commit-76b95cf-contains-an-out-of-bounds-read-in-the)
- [EIPStackGroup OpENer buffer overflow in GetAttributeList](https://junglewise.ai/threats/cve-2026-75350-eipstackgroup-opener-v2-3-master-commit-76b95cf-contains-a-buffer)
- [EIPStackGroup OpENer expired pointer dereference in EtherNet/IP CPF](https://junglewise.ai/threats/cve-2026-75347-eipstackgroup-opener-v2-3-and-master-up-to-commit-76b95cf-contain)
- [EIPStackGroup OpENer out-of-bounds read in Connection Manager](https://junglewise.ai/threats/cve-2026-75349-eipstackgroup-opener-v2-3-0-master-up-to-commit-76b95cf-contains)
- [EIPStackGroup OpENer out-of-bounds read in EtherNet/IP TCP parser](https://junglewise.ai/threats/cve-2026-75348-an-out-of-bounds-read-vulnerability-exists-in-eipstackgroup)