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Full vulnerability report · 2026
CVE-2026-66281High confidence

Authenticated Denial-of-Service in Zigbee Discover Attributes Handling

Silicon Labs · EmberZNet

6.0MediumCVSS 4.0
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.22% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Silicon Labs EmberZNet and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-108181

No EUVD known-exploited evidence

In EmberZNet 9.1.1 and earlier, a malformed Discover Attributes command can result in a loop with unreachable exit condition (infinite loop). These messages must come from a device that has already joined the network. Only devices supporting manufacturer-specific clusters are impacted.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
6.0 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
01

What, why and how

In EmberZNet 9.1.1 and earlier, a malformed Discover Attributes command can result in a loop with unreachable exit condition (infinite loop). These messages must come from a device that has already joined the network. Only devices supporting manufacturer-specific clusters are impacted.

What

In EmberZNet 9.1.1 and earlier, a malformed Discover Attributes command can result in a loop with unreachable exit condition (infinite loop). These messages must come from a device that has already joined the network. Only devices supporting manufacturer-specific clusters are impacted.

Why

A malformed condition prevents a loop from making progress or terminating, allowing resource exhaustion.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

In EmberZNet 9.1.1 and earlier, a malformed Discover Attributes command can result in a loop with unreachable exit condition (infinite loop). These messages must come from a device that has already joined the network. Only devices supporting manufacturer-specific clusters are impacted.

Why

A malformed condition prevents a loop from making progress or terminating, allowing resource exhaustion.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Loop with Unreachable Exit Condition ('Infinite Loop') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-835 ↗

CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop'). The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkCWE-835
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-108181Official EUVD mapping

In EmberZNet 9.1.1 and earlier, a malformed Discover Attributes command can result in a loop with unreachable exit condition (infinite loop). These messages must come from a device that has already joined the network. Only devices supporting manufacturer-specific clusters are impacted.

Official EUVD record ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
EmberZNet: ≤ 9.1.1
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 22 Oct 2026 · Last source change 23 Oct 2026, 10:56 UTC · CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-10-23
European sourceENISA EUVD · EUVD-2026-108181
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enrichment underway

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2026-108181 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-108181"}
    ENISA EUVD ↗
  2. Catalogue recordCVE added to the BlackTree catalogue.
    Official European vulnerability authority ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: removed vendor advisory: github.com/A-00000590.md.
    Before
    vendor advisory: github.com/A-00000590.md
    After
    no authoritative guidance recorded
    CNA ↗
  4. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: github.com/A-00000590.md; removed remediation: euvd.enisa.europa.eu/EUVD-2026-108181.
    Before
    remediation: euvd.enisa.europa.eu/EUVD-2026-108181
    After
    vendor advisory: github.com/A-00000590.md
    github.com ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    silabs.com EmberZNet 0 ≤9.1.1 · Fixed: No fixed version is explicitly recorded in the available ENISA EUVD evidence.
    After
    EmberZNet: ≤ 9.1.1 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  6. CVSS scoreCVSS scoring authority changed from Other authority to CNA; the displayed base score remained 6.0.
    Before
    6.0 (CVSS 4.0 · Other authority · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
    After
    6.0 (CVSS 4.0 · CNA · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
    CNA ↗
  7. Affected versionsThe structured affected or fixed version information changed.
    Before
    ENISA EUVD does not provide a structured affected-product range for this provisional report. · Fixed: No fixed version is explicitly recorded in the available ENISA EUVD evidence.
    After
    silabs.com EmberZNet 0 ≤9.1.1 · Fixed: No fixed version is explicitly recorded in the available ENISA EUVD evidence.
    Official European vulnerability authority ↗
  8. SeveritySeverity changed from Unknown to Medium.
    Before
    Unknown
    After
    Medium
    Other authority ↗
  9. CVSS scoreCVSS score changed from not recorded to 6.0 (CVSS 4.0 · Other authority · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N).
    Before
    not recorded
    After
    6.0 (CVSS 4.0 · Other authority · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
    Other authority ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-108181↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-66281 · cve.blacktree.nl