CVE-2023-25556
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 · uneditedA CWE-287: Improper Authentication vulnerability exists that could allow a device to be compromised when a key of less than seven digits is entered and the attacker has access to the KNX installation.
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 confidenceAn improper authentication vulnerability exists in KNX devices where entering a key of less than seven digits allows attackers with physical or logical access to the KNX installation to compromise the device. The weak key length fails to provide adequate entropy for secure authentication.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.0= 1.0= 1.0= 1.2= 1.0= 1.0= 1.0= 1.1= 0.1CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 checksWork through these to decide whether this CVE applies to you.
-
Identify affected Merten device modelsReview your KNX installation inventory or physically inspect devices for model numbers: Merten Instabus Tastermodul 1fach/2fach, Tasterschnittstelle 4fach Plus, Knx Argus 180, Jalousie aktor, Uni Dimmaktor, or Schaltakt. Check product labels or documentation.Affected if Any of these specific Merten device models are present in the KNX installation
-
Check firmware versionConnect to the device using ETS (Engineering Tool Software) or the device's management interface. Navigate to the device properties or parameters section to view the firmware version.Affected if Firmware version equals 1.0, 1.2, or 0.1 for the affected models listed in the CVE
-
Verify authentication key configurationAccess the device configuration through ETS or the device's web interface. Locate the authentication or security key settings. Count the number of digits in the configured key.Affected if The configured authentication key contains fewer than 7 digits (the key length is weak)
-
Confirm device is accessibleVerify the KNX device is reachable on the network or bus. Check physical access controls to the device and network segment.Affected if Device is accessible to potential attackers (logical network access or physical proximity exists
You are affected if you have any of the listed Schneider Electric Merten devices with firmware version 1.0, 1.2, or 0.1 AND the authentication key is configured with fewer than 7 digits.
Generated from the published advisory. Verify against your own configuration.
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 dataEnforce minimum key length of seven or more digits in the device's authentication mechanism and restrict physical and network access to the KNX installation to prevent unauthorized key entry.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-25556 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-25556 in production — separate from our analysis above.
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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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