CVE-2025-40593Network attack vector

Authenticated denial of service via arbitrary SFTP files

Published Jul 8, 2025 · Updated Jul 8, 2025

Improper input validation in Siemens SIMATIC CN 4100 before 4.0 allows remote authenticated users to cause a service interruption via SFTP. The application accepts arbitrary files stored in the device's SFTP folder as control input without adequate validation. Valid SFTP credentials and network access are required, and successful exploitation interrupts availability without reported data exposure or modification.

CVSS severity6.5
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Siemens SIMATIC CN 4100 before 4.0 allows remote authenticated users to cause a service interruption via SFTP. The application accepts arbitrary files stored in the device's SFTP folder as control input without adequate validation. Valid SFTP credentials and network access are required, and successful exploitation interrupts availability without reported data exposure or modification.

The record

CVE
CVE-2025-40593
Published
Jul 8, 2025
Updated
Jul 8, 2025
Vendor
Siemens
Product
SIMATIC CN 4100
Classifications
CWE-20, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 8, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 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

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

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

Published CVSS scores

7.1Siemens ProductCERTCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
6.5Siemens ProductCERTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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