How severe is CVE-2025-40940?

CVE-2025-40940 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-40940 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-40940?

CVE-2025-40940 affects Siemens Simatic Cn 4100 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-40940?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-40940 have an EU (EUVD) identifier?

Yes. CVE-2025-40940 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201916.

When was CVE-2025-40940 published?

CVE-2025-40940 was published on 2025-12-09 and last updated on 2026-06-17.

CVE-2025-40940

CVE-2025-40940 is a medium-severity vulnerability in Siemens Simatic Cn 4100 Firmware with a CVSS 3.x base score of 4.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: Medium (CVSS 3.x base score 4.9)
CVSS v4: 6.9
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-201916
Weakness: CWE-200
Affected product: Siemens Simatic Cn 4100 Firmware
Published: 2025-12-09
Last modified: 2026-06-17

Description

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1). The affected application exhibits inconsistent SNMP behavior, such as unexpected service availability and unreliable configuration handling across protocol versions. This could allow an attacker to access sensitive data, potentially leading to a breach of confidentiality.

Frequently asked questions

What is CVE-2025-40940?: A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1). The affected application exhibits inconsistent SNMP behavior, such as unexpected service availability and unreliable configuration handling across protocol versions. This could allow an attacker to access sensitive data, potentially leading to a breach of confidentiality.
How severe is CVE-2025-40940?: CVE-2025-40940 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-40940 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-40940?: CVE-2025-40940 affects Siemens Simatic Cn 4100 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-40940?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40940 have an EU (EUVD) identifier?: Yes. CVE-2025-40940 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201916.
When was CVE-2025-40940 published?: CVE-2025-40940 was published on 2025-12-09 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:o:siemens:simatic_cn_4100_firmware:*:*:*:*:*:*:*:*

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