CVE-2025-40938: A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1)

Q: How do I fix CVE-2025-40938?

simatic cn 4100 firmware: upgrade to 4.0.1. Exact commands for each OS are on this page.

Q: Is CVE-2025-40938 being exploited?

CVE-2025-40938 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-40938 affect?

CVE-2025-40938 affects simatic cn 4100 firmware. Severity is high (CVSS 8.1). A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1). The affected device stores sensitive information in the firmware. This could allow an attacker to access and misuse this information, potentially impacting the

Q: How urgent is CVE-2025-40938?

Priority 41/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 8.1REMOTEUPGRADE

CVE-2025-40938 is a high-severity flaw (CVSS 8.1) affecting simatic cn 4100 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1). The affected device stores sensitive information in the firmware. This could allow an attacker to access and misuse this information, potentially impacting the device’s confidentiality, integrity, and availability.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 70%)
CISA exploited list	No
Weakness	CWE-798
Published	2025-12-09
Last modified	2026-10-23

Publisher (CNA): Siemens AG · Vendor: siemens

Am I affected?

Timeline

2025-12-09 16:17 UTCPublished CVE record published
2026-10-23 22:10 UTCUpdated Record last modified

siemens simatic cn 4100 firmware UPGRADE

Affected: < 4.0.1

Fixed in: 4.0.1

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

Fedora 46 · kwin-zones · FIXED · 1.0.13-1.fc46 · FEDORA-2026-95888f332b · source

sudo dnf upgrade --advisory=FEDORA-2026-95888f332b

Fedora ELN · nginx-mod-brotli · FIXED · 1.0.0~rc-16.eln159 · FEDORA-2026-501a6a8273 · source

sudo dnf upgrade --advisory=FEDORA-2026-501a6a8273

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-40938?

simatic cn 4100 firmware: upgrade to 4.0.1. Exact commands for each OS are on this page.

Is CVE-2025-40938 being exploited?

CVE-2025-40938 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-40938 affect?

CVE-2025-40938 affects simatic cn 4100 firmware. Severity is high (CVSS 8.1). A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1). The affected device stores sensitive information in the firmware. This could allow an attacker to access and misuse this information, potentially impacting the

How urgent is CVE-2025-40938?

Priority 41/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-22925 HIGH 7.5 UPGRADE A vulnerability has been identified in SIMATIC CN 4100 (All versions < V5.0)
CVE-2023-29131 HIGH 7.4 UPGRADE A vulnerability has been identified in SIMATIC CN 4100 (All versions < V2.5)
CVE-2025-40937 HIGH 8.3 UPGRADE A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1)
CVE-2025-40940 MEDIUM 4.9 UPGRADE A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1)
CVE-2025-40941 MEDIUM 4.3 UPGRADE A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1)

References

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