---
id: CVE-2026-78012
title: >-
  An issue in the NetStaX EtherNet/IP Stack prior to v5.6.1 could allow a large
  Class 3 explicit-message request to exceed the application-side receive buffer
  without generating an error or warning
summary: >-
  An issue in the NetStaX EtherNet/IP Stack prior to v5.6.1 could allow a large
  Class 3 explicit-message request to exceed the application-side receive buffer
  without generating an error or warning. The result could be memory corruption,
  a…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-121
published: '2026-09-01'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T15:28:33.090'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78012'
references:
  - url: >-
      https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-246-07.json
    label: ics-cert@hq.dhs.gov
  - url: >-
      https://pyramidsolutions.com/netstax-v-5-6-1-protecting-against-silent-buffer-overflow-in-ethernet-ip-stack-explicit-messages/
    label: ics-cert@hq.dhs.gov
  - url: 'https://www.cisa.gov/news-events/ics-advisories/icsa-26-246-07'
    label: ics-cert@hq.dhs.gov
tags:
  - nvd
epss: 0.00649
epssPercentile: 0.48953
ingestedAt: '2026-09-05T20:44:35.056Z'
---

## Overview

An issue in the NetStaX EtherNet/IP Stack prior to v5.6.1 could allow a large Class 3 explicit-message request to exceed the application-side receive buffer without generating an error or warning. The result could be memory corruption, a device crash, or a potential remote attack vector without the originating device receiving a CIP error indicating that the request could not be processed.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.