---
id: CVE-2025-40939
title: A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1)
summary: >-
  A vulnerability has been identified in SIMATIC CN 4100 (All versions <
  V4.0.1). The affected device contains a USB port which allows unauthenticated
  connections. This could allow an attacker with physical access to the device
  to trigger …
severity: medium
cvss: 4.6
cvssVector: 'CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-284
vendor: siemens
product: simatic_cn_4100_firmware
affected:
  - simatic_cn_4100_firmware < 4.0.1
patched:
  - simatic_cn_4100_firmware 4.0.1
published: '2025-12-09'
updated: '2026-10-07'
sourceUpdated: '2026-10-07T20:10:01.970'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-40939'
references:
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-416652.html'
    label: productcert@siemens.com
tags:
  - nvd
epss: 0.00213
epssPercentile: 0.10581
ingestedAt: '2026-10-07T20:46:46.792Z'
---

## Overview

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1). The affected device contains a USB port which allows unauthenticated connections. This could allow an attacker with physical access to the device to trigger reboot that could cause denial of service condition.

## Affected

- `simatic_cn_4100_firmware < 4.0.1`

## Remediation

Upgrade past the affected range:

- `simatic_cn_4100_firmware 4.0.1`