CVE-2025-40938Network attack vector

Device compromise via credentials embedded in firmware

Published Dec 9, 2025 · Updated Dec 9, 2025

Use of hard-coded credentials in Siemens SIMATIC CN 4100 before 4.0.1 allows remote attackers to access sensitive firmware data. The firmware embeds sensitive information, but Siemens has not disclosed its storage locus, the credentials involved, or the retrieval path. Exploitation requires network reachability but no privileges or user interaction, and Siemens rates attack complexity as high; misuse can compromise the device.

CVSS severity9.2
Critical
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use of hard-coded credentials in Siemens SIMATIC CN 4100 before 4.0.1 allows remote attackers to access sensitive firmware data. The firmware embeds sensitive information, but Siemens has not disclosed its storage locus, the credentials involved, or the retrieval path. Exploitation requires network reachability but no privileges or user interaction, and Siemens rates attack complexity as high; misuse can compromise the device.

The record

CVE
CVE-2025-40938
Published
Dec 9, 2025
Updated
Dec 9, 2025
Vendor
Siemens
Product
SIMATIC CN 4100
Classifications
CWE-798, T1552
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <V4.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SIMATIC CN 4100version=0 <V4.0.1

Published CVSS scores

9.2Siemens AGCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1Siemens AGCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
T1552Unsecured Credentials

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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