---
id: "CVE-2026-82945"
kind: "vulnerability"
aliases: ["CVE-2026-82945"]
title: "SOEM: a malicious EtherCAT device can corrupt memory during configuration"
severity: "medium"
cvss: 6.5
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["embedded", "ethercat", "industrial-control", "package", "robotics", "soem"]
not_affected_if: ["isolated-bus", "newer-version", "vetted-devices-only"]
published_at: "2026-10-26T09:16:36+00:00"
first_seen_at: "2026-10-26T09:29:16+00:00"
updated_at: "2026-10-26T09:30:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-82945", "first_seen_at": "2026-10-26T09:29:16+00:00"}]
---

# SOEM: a malicious EtherCAT device can corrupt memory during configuration

SOEM, an open-source EtherCAT master library, writes device configuration data into a fixed-size array without bounds checking. A malicious device that presents more than EC_MAXFMMU configuration blocks can overwrite adjacent memory and disrupt later operations.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the SOEM version in use: unknown exact command, the sources do not name a package manager or file
- Search the project for `EC_MAXFMMU` and the device configuration code path to see if it is compiled in
- Review whether the master talks to untrusted or third-party EtherCAT slave devices

## Fix

- Upgrade SOEM past `2.0.0`; the sources do not name the fixed release, check the upstream SOEM repository
- Until patched, restrict the EtherCAT network to trusted devices

## Timeline

- 2026-10-26T09:29:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-82945

## From the sources

SOEM version 2.0.0 and earlier contains a vulnerability during device configuration where a malicious device can cause memory corruption. The software writes configuration data to a fixed-size array without checking if the array index exceeds its maximum size of EC_MAXFMMU entries. A device presenting more than EC_MAXFMMU configuration blocks can force writes beyond the array boundary, corrupting adjacent memory structures and potentially disrupting subsequent operations.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_