Classic Buffer OverflowWeakness · CWE-120

CVE-2025-40815

HIGH · 7.2 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 →

78/100

Remediation priority · High

Remotely reachable Zero-click

Official description

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 properly validate the structure of TCP packets in several methods. This could allow an attacker to cause buffer overflows, get control over the instruction counter and run custom code.

Technical summary

dbcve analysis · high confidence

Multiple Siemens LOGO! PLC variants contain a buffer overflow vulnerability in TCP packet handling. Attackers sending specially crafted TCP packets with malformed structures can overflow buffers, hijack the instruction pointer, and execute arbitrary code. This is a network-based RCE vulnerability affecting all versions of the listed LOGO! device models.

MitigationApply network segmentation and firewalls to isolate LOGO! devices from untrusted networks; contact Siemens for available firmware updates; disable TCP communications if not required for the process.

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

CVSS breakdown

From the vector

Attack vector: Network
Complexity: Low
Privileges: High
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

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

Am I affected?

dbcve checks

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

Identify Siemens LOGO! PLC devices on your network

Review your network inventory, scan for Siemens LOGO! device signatures, or check your industrial control system documentation for LOGO! PLC models

Affected if You have any Siemens LOGO! PLC variants deployed
Determine the firmware version of your LOGO! device

Access the device web interface or use Siemens LOGO! Soft Comfort software to read the firmware version from the device properties

Affected if The installed firmware version is any version of the listed LOGO! models (the vulnerability affects all versions)
Verify TCP communication is enabled on the device

Check the device configuration settings in LOGO! Soft Comfort or the device web interface for TCP communication parameters

Affected if TCP/IP communication is enabled in the device configuration
Check network exposure of the LOGO! device

Review firewall rules, network segmentation, and access control lists to determine if the LOGO! device TCP ports are accessible from networks outside your trusted control system zone

Affected if The device TCP ports are reachable from untrusted or non-segmented network segments

You are affected if you have any Siemens LOGO! PLC with TCP enabled and network accessibility, since the vulnerability exists in all versions of the affected models.

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

Remediation

From vendor data

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Apply network segmentation and firewalls to isolate LOGO! devices from untrusted networks; contact Siemens for available firmware updates; disable TCP communications if not required for the process.

Have this fixed Scoped from the published advisory

Consultation8.0 h
Implementation16.0 h
Testing12.0 h
Review / QA4.0 h

40.0 hours of engineering $7,000

Get help mitigating

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Scan for this in your stack

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References

Primary sources

cert-portal.siemens.com
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-40815 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2025-40815?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsA vendor remedy is published

Severity 7.2 High

Exploit likelihood EPSS, next 30 days 0.4%

Remediation

A high-priority fix

Have this fixed 40 hrs · High

Typical engagement from $7,000

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2025-40815 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

CVSS breakdown

Am I affected?

Remediation

References