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Simatic Cn 4100 Firmware CVE-2025-40593

| EUVDEUVD-2025-20435 MEDIUM
Improper Input Validation (CWE-20)
2025-07-08 productcert@siemens.com
6.5
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
Impact

Service disruption affecting availability. In critical infrastructure, DoS can have cascading effects on dependent systems. With a CVSS score of 6.5 (MEDIUM), this represents a moderate risk.

Exploit ScenarioDerived

An attacker sends specially crafted requests that cause excessive resource consumption (CPU, memory, disk) or trigger a crash in the target application.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 16, 2026

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0). The affected application allows to control the device by storing arbitrary files in the SFTP folder of the device. This could allow an attacker to cause a denial of service condition.

Earlier versions of this analysis (1)
v1 Mar 16, 2026 - 04:21 CVSS 6.5

RemediationAI

Implement rate limiting and input validation. Use timeout mechanisms for resource-intensive operations. Deploy DDoS protection where applicable.

Affected VersionsENISA

SIMATIC CN 4100 0 <V4.0

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

A denial of service vulnerability allows an attacker to disrupt the normal functioning of a system, making it unavailable to legitimate users. This vulnerability is classified as Improper Input Validation (CWE-20).

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Executive ViewAI

Why It Matters

Organizations using A vulnerability should be aware of notable risk from CVE-2025-40593, a input validation vulnerability rated CVSS 6.5. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Moderate
Compensating Controls

Apply vendor patch. If patching is delayed: deploy WAF rules, restrict network access, enable logging.

Threat Intelligence Overview

EPSS Score
0.1%
Top 67% exploitable
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

CVE-2023-29131 CRITICAL
10.0 Jul 11

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V2.5). Rated critical severity (CVSS 10.0), this

CVE-2024-32741 CRITICAL
10.0 May 14

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V3.0). Rated critical severity (CVSS 10.0), this

CVE-2023-29130 CRITICAL
10.0 Jul 11

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V2.5). Rated critical severity (CVSS 10.0), this

CVE-2023-49621 CRITICAL
9.8 Jan 09

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V2.7). Rated critical severity (CVSS 9.8), this v

CVE-2024-32740 CRITICAL
9.8 May 14

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V3.0). Rated critical severity (CVSS 9.8), this v

CVE-2025-40938 CRITICAL
9.2 Dec 09

SIMATIC CN 4100 devices running firmware versions below V4.0.1 store sensitive credentials and keys in a hard-coded, rec

CVE-2023-49251 HIGH
8.8 Jan 09

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V2.7). Rated high severity (CVSS 8.8), this vulne

CVE-2025-40937 HIGH
8.7 Dec 09

Authenticated command injection in the REST API of Siemens SIMATIC CN 4100 firmware versions below V4.0.1 allows a user

CVE-2024-32742 HIGH
7.6 May 14

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V3.0). Rated high severity (CVSS 7.6), this vulne

CVE-2023-49252 HIGH
7.5 Jan 09

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V2.7). Rated high severity (CVSS 7.5), this vulne

CVE-2025-40940 MEDIUM
6.9 Dec 09

Inconsistent SNMP behavior in Siemens SIMATIC CN 4100 firmware versions below V4.0.1 lets an authenticated, highly privi

CVE-2025-40941 MEDIUM
5.3 Dec 09

SIMATIC CN 4100 devices running firmware versions before V4.0.1 expose server information in their responses, enabling a

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