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Vulnerabilities

Vulnerability · CVE-2025-40939

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1).

Published Dec 9, 2025 · catalog updated Dec 9, 2025 · Siemens SIMATIC CN 4100

Last checked Oct 28, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-40939. EPSS is 0.21%. Act only if a listed version of Siemens SIMATIC CN 4100 is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.21%
Remediation
Version ranges on file
Affected products
vendor Siemens SIMATIC CN 4100 0 <V4.0.1

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Siemens SIMATIC CN 4100 0 <V4.0.10 <V4.0.1

How to fix CVE-2025-40939

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-40939. EPSS is 0.21%. Act only if a listed version of Siemens SIMATIC CN 4100 is installed.

Which versions are affected?

Compare what you have installed with Siemens SIMATIC CN 4100 0 <V4.0.1 0 <V4.0.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.21%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 9, 2025 · EUVD

    Detected

    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.

  2. Dec 9, 2025 · EUVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2025-40939

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-40939

    30-day exploitation probability 0.21%

    first.org
  • EUVDVulnerability recordEUVD-2025-201917

    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 c

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 28, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 28, 2026
  • CVE.orgOct 28, 2026
  • EUVDOct 27, 2026