dbcve.org
Z Wave S0 FirmwareOperating system · Silabs

CVE-2018-19983

MEDIUM · 6.5 CVSS v3.0 Published 2018-12-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
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
An issue was discovered on Sigma Design Z-Wave S0 through S2 devices. An attacker first prepares a Z-Wave frame-transmission program (e.g., Z-Wave PC Controller, OpenZWave, CC1110, etc.). Next, the attacker conducts a DoS attack against the Z-Wave S0 Security version product by continuously sending divided "Nonce Get (0x98 0x81)" frames. The reason for dividing the "Nonce Get" frame is that, in security version S0, when a node receives a "Nonce Get" frame, the node produces a random new nonce and sends it to the Src node of the received "Nonce Get" frame. After the nonce value is generated and transmitted, the node transitions to wait mode. At this time, when "Nonce Get" is received again, the node discards the previous nonce value and generates a random nonce again. Therefore, because the frame is encrypted with previous nonce value, the received normal frame cannot be decrypted.

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 · high confidence

This CVE describes a denial-of-service vulnerability in Z-Wave S0 security protocol where an attacker continuously sends fragmented 'Nonce Get' frames to a target device. When the device receives a 'Nonce Get' frame, it generates a new random nonce and transitions to wait mode. Repeated 'Nonce Get' frames cause the device to discard previously generated nonces, rendering legitimate encrypted frames undecipherable since they were encrypted with the discarded nonce value.

MitigationApply vendor firmware updates for affected Sigma Design Z-Wave devices when available. For defense-in-depth, implement network segmentation to restrict unauthorized Z-Wave traffic and monitor for unusual Nonce Get frame patterns.

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
Z Wave S0 FirmwareOperating system
Affected:all versions
Z Wave S2 FirmwareOperating system
Affected:all versions

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
None
Integrity
None
Availability
High

CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 Z-Wave devices in your environment
    Inventory all Z-Wave enabled devices (controllers, switches, sensors, locks) by reviewing network device lists, controller dashboards, or using Z-Wave discovery tools
    Affected if Any Z-Wave device is present in the environment using S0 or S2 firmware
  2. Confirm S0 security protocol is enabled
    Access your Z-Wave controller configuration and verify whether S0 security class is included in the network configuration or device associations. S0 is typically indicated during device inclusion when security keys are exchanged.
    Affected if S0 security protocol is enabled on any Z-Wave device (the vulnerability exists in S0 by design)
  3. Monitor for abnormal Nonce Get frame frequency
    Capture Z-Wave network traffic using a Z-Wave sniffer or controller logging features. Look for a high frequency of 'Nonce Get' command class frames (Command Class 0x50) sent in succession, which is not typical for normal device operation.
    Affected if Repeated Nonce Get frames are observed beyond normal pairing/initialization behavior
  4. Check for decryption failures
    Review device or controller logs for errors indicating 'decryption failed', 'nonce expired', or 'authentication failure' on encrypted frames that were previously working
    Affected if Legitimate encrypted Z-Wave frames become undecipherable and authentication failures increase after sustained Nonce Get activity

If you have Z-Wave devices with S0 security enabled and observe either a high frequency of Nonce Get frames or legitimate encrypted frames becoming undecipherable, your environment is likely affected by this vulnerability.

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

Apply vendor firmware updates for affected Sigma Design Z-Wave devices when available. For defense-in-depth, implement network segmentation to restrict unauthorized Z-Wave traffic and monitor for unusual Nonce Get frame patterns.

Fix this in Z Wave S0 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing16.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,760
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $15,616.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-19983 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2018-19983 in production — separate from our analysis above.

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.

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