CVE-2023-4346
highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.014 · 72 %ileEUUSadded 2026-07-15remediate by 2026-07-29
required action Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
EPSS · scored 2026-10-26
KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability
KNX devices that use KNX Connection Authorization and support Option 1 are, depending on the implementation, vulnerable to being locked and users being unable to reset them to gain access to the device. The BCU key feature on the devices can be used to create a password for the device, but this password can often not be reset without entering the current password. If the device is configured to interface with a network, an attacker with access to that network could interface with the KNX installation, purge all devices without additional security options enabled, and set a BCU key, locking the device. Even if a device is not connected to a network, an attacker with physical access to the device could also exploit this vulnerability in the same way.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
No vendor fix yet; a mitigation is available.
- MitigationKNX devices using Connection Authorization Option 1 Style in which no BCU Key is currently setcisa_csaf_ot
The KNX Association also recommends developers always set the BCU Key in every KNX Project that is already finished and will be commissioned in the future. Handover the BCU Key as part of the Project Documentation to the Building Owner.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (4)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- ICSA-23-236-01KNX Protocol2023-08-24icsa · cisa_csaf_otUS
Successful exploitation of this vulnerability could cause users to lose access to their device, potentially with no way to reset the device.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7)
External citations — patches, advisories, analysis.
- https://cxsecurity.com/cveshow/CVE-2023-4346/cnnvd
- https://www.auscert.org.au/bulletins/ESB-2023.4861cnnvd
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01cnnvd
- https://www.knx.org/knx-en/for-professionals/benefits/knx-secure/index.phpPatchcnnvd
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01enisa_euvd
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346US Government Resourcenvd
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01Third Party AdvisoryUS Government Resourcenvd
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