CVE-2023-4346Known exploitationNetwork attack vector

Persistent device lockout via unauthorized BCU key

Published Aug 29, 2023 · Updated Jul 16, 2026

Account lockout in KNX Protocol Connection Authorization Option 1 allows remote attackers to deny device access by setting a BCU key. A network-accessible installation permits unauthenticated device purging and accepts a new BCU key when no key or additional security option is set. Network access is the remote gate, while physically proximate attackers can perform the same action; loss of the new key can make manufacturer return necessary.

CVSS severity7.5
High
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Account lockout in KNX Protocol Connection Authorization Option 1 allows remote attackers to deny device access by setting a BCU key. A network-accessible installation permits unauthenticated device purging and accepts a new BCU key when no key or additional security option is set. Network access is the remote gate, while physically proximate attackers can perform the same action; loss of the new key can make manufacturer return necessary.

The record

CVE
CVE-2023-4346
Published
Aug 29, 2023
Updated
Jul 16, 2026
Vendor
KNX Association
Product
KNX Protocol Connection Authorization Option 1
Classifications
CWE-645, CAPEC-2, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 29, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

KNX Association · KNX Protocol Connection Authorization Option 1version=0

Published CVSS scores

7.5CISACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-645Overly Restrictive Account Lockout Mechanism
CAPEC-2Inducing Account Lockout
T0814Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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