# CVE-2023-4346: KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability

> CVE-2023-4346: KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability. CVSS 7.5 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2023-4346
Last updated: 2026-07-16T05:16:16Z

- Published: 2023-08-29 19:38 UTC · Updated: 2026-07-16 05:16 UTC · Assigner: icscert
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS: 1.4%, 72th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2026-07-15, federal due date 2026-07-29, ransomware use: Unknown
- CWE: CWE-645

## Description

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.

## CISA 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.

## Affected vendors and products

- KNX Association: KNX Protocol Connection Authorization Option 1

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2023-4346)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2023-4346)
- [https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01](https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2023-4346 · Markdown: https://rewindex.com/cve/CVE-2023-4346.md · JSON: https://rewindex.com/api/v1/cves/CVE-2023-4346 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:13:30.204Z