CVE-2025-40939

Unknown Unknown - Not Provided

BaseFortify

Publication date: 2025-12-09

Last updated on: 2025-12-16

Assigner: Siemens AG

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-12-09

Last Modified

2025-12-16

Generated

2026-07-06

AI Q&A

2025-12-09

EPSS Evaluated

2026-07-05

NVD

CVE-2025-40939

EUVD

EUVD-2025-201917

Affected Vendors & Products

Vendor	Product	Version / Range
siemens	simatic_cn_4100_firmware	to 4.0.1 (inc)
siemens	simatic_cn_4100	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-284	The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Attack-Flow Graph

Executive Summary

This vulnerability exists in the SIMATIC CN 4100 device (all versions before V4.0.1) which has a USB port allowing unauthenticated connections. An attacker with physical access to the device can use this USB port to trigger a reboot, potentially causing a denial of service condition.

Impact Analysis

The vulnerability can impact you by allowing an attacker with physical access to the device to cause it to reboot unexpectedly. This can lead to a denial of service condition, disrupting the availability of the device and any services relying on it.

Mitigation Strategies

To mitigate this vulnerability, restrict physical access to the SIMATIC CN 4100 device to prevent unauthorized use of the USB port. Ensure that only trusted personnel can access the device physically, as the vulnerability requires physical access to trigger a reboot causing denial of service.

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