CVE-2025-40939

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 v3.1 Score

4.6

MEDIUM

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-284 CWE-284

Affected Products

Vendor	Product	Versions
siemens	simatic_cn_4100_firmware	< 4.0.1
siemens	simatic_cn_4100	All

References

Advisories & Patches

https://cert-portal.siemens.com/productcert/html/ssa-416652.html

Frequently Asked Questions

What is CVE-2025-40939? +

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. It has a CVSS v3.1 base score of 4.6 (MEDIUM).

How severe is CVE-2025-40939? +

CVE-2025-40939 has a CVSS v3.1 score of 4.6 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-40939? +

CVE-2025-40939 affects products from siemens, specifically: simatic_cn_4100, simatic_cn_4100_firmware. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-40939? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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