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Missing AuthenticationWeakness · CWE-306

CVE-2025-40816

HIGH · 7.6 CVSS v3.1 Published 2025-11-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
81/100
Remediation priority · High
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability has been identified in LOGO! 12/24RCE (6ED1052-1MD08-0BA2) (All versions), LOGO! 12/24RCEo (6ED1052-2MD08-0BA2) (All versions), LOGO! 230RCE (6ED1052-1FB08-0BA2) (All versions), LOGO! 230RCEo (6ED1052-2FB08-0BA2) (All versions), LOGO! 24CE (6ED1052-1CC08-0BA2) (All versions), LOGO! 24CEo (6ED1052-2CC08-0BA2) (All versions), LOGO! 24RCE (6ED1052-1HB08-0BA2) (All versions), LOGO! 24RCEo (6ED1052-2HB08-0BA2) (All versions), SIPLUS LOGO! 12/24RCE (6AG1052-1MD08-7BA2) (All versions), SIPLUS LOGO! 12/24RCEo (6AG1052-2MD08-7BA2) (All versions), SIPLUS LOGO! 230RCE (6AG1052-1FB08-7BA2) (All versions), SIPLUS LOGO! 230RCEo (6AG1052-2FB08-7BA2) (All versions), SIPLUS LOGO! 24CE (6AG1052-1CC08-7BA2) (All versions), SIPLUS LOGO! 24CEo (6AG1052-2CC08-7BA2) (All versions), SIPLUS LOGO! 24RCE (6AG1052-1HB08-7BA2) (All versions), SIPLUS LOGO! 24RCEo (6AG1052-2HB08-7BA2) (All versions). Affected devices do not conduct certain validations when interacting with them. This could allow an unauthenticated remote attacker to manipulate the devices IP address, which means the device would not be reachable.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Siemens LOGO! programmable logic controllers (PLCs) fail to validate incoming network requests when manipulated, allowing an unauthenticated remote attacker to change the device's IP address. This renders the device unreachable at its original network configuration, effectively causing a denial of service.

MitigationImplement network segmentation to isolate PLCs from untrusted networks, deploy IP address monitoring to detect unauthorized changes, and apply compensating controls until vendor firmware updates are available.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Siemens LOGO! PLCs in your network
    Review network device inventory or use network scanning to identify devices with Siemens LOGO! characteristics (check manufacturer OUI, device fingerprints, or consult plant network diagrams)
    Affected if A Siemens LOGO! PLC device is present in the environment
  2. Determine network exposure of LOGO! devices
    Review firewall rules, network segmentation, and access control lists to check whether the PLC network management interfaces are reachable from untrusted or external networks
    Affected if The PLC is accessible from untrusted network segments without network segmentation or filtering
  3. Verify current IP configuration against expected baseline
    Query the LOGO! device for its current IP address (via web interface, TIA Portal, or network tools) and compare it to the documented baseline configuration
    Affected if The device IP address differs from the expected baseline configuration without authorized change
  4. Confirm IP address change monitoring capability
    Check if you have network monitoring, DHCP lease tracking, or IP address change detection tools logging or alerting on PLC IP modifications
    Affected if No monitoring is in place to detect unauthorized IP address changes on the PLC

You are affected if you have a Siemens LOGO! PLC exposed to untrusted networks without IP change monitoring, and your device IP address has changed from its expected configuration.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement network segmentation to isolate PLCs from untrusted networks, deploy IP address monitoring to detect unauthorized changes, and apply compensating controls until vendor firmware updates are available.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-40816 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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