What is CVE-2025-40939?

CVE-2025-40939 is a medium-severity vulnerability in Siemens Simatic Cn 4100, classified under Improper Access Control. CVSS score: 4.6/10. Published 2025-12-09.

How severe is CVE-2025-40939?

Medium severity. CVSS v3 base score is 4.6 out of 10.

Vulnerability in Siemens Simatic Cn 4100

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 re…

EPSS: 0.000 (14.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Siemens Simatic Cn 4100 — versions 0

Weakness classification (CWE)

CWE-284 — Improper Access Control

References

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

Frequently asked questions

What is CVE-2025-40939?: CVE-2025-40939 is a medium-severity vulnerability in Siemens Simatic Cn 4100, classified under Improper Access Control. CVSS score: 4.6/10. Published 2025-12-09.
How severe is CVE-2025-40939?: Medium severity. CVSS v3 base score is 4.6 out of 10.