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Z Wave S0 Firmware CVE-2018-19983

MEDIUM
Use of Insufficiently Random Values (CWE-330)
2018-12-09 cve@mitre.org
6.5
CVSS 3.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Cryptographic random values
Impact

CVSS score of 6.5 (MEDIUM). Attack characteristics: adjacent network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAI

An issue was discovered on Sigma Design Z-Wave S0 through S2 devices. Rated medium severity (CVSS 6.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

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Technical ContextAI · show details

This vulnerability is classified under CWE-330. 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. Affected products include: Silabs Z-Wave S0 Firmware, Silabs Z-Wave S2 Firmware.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.5 MEDIUM
AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

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.

Threat Intelligence Overview

EPSS Score
0.5%
Top 63% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.5%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:o:silabs:z-wave_s0_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:silabs:z-wave_s2_firmware:-:*:*:*:*:*:*:*

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