CVE-2023-4346
7.5, high Known exploitedKNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability
- CVSS
- 7.5, high high CVSS v3.1
- EPSS, next 30 days
- 1% higher than 69.8% of scored CVEs
- Exploitation
- Confirmed in the wild
- Published
- 29 Aug 20233 years ago
Known exploited
CISA added this to the Known Exploited Vulnerabilities Catalog on 15 Jul 2026. US federal agencies had to remediate by 29 Jul 2026, a deadline that has passed.
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.
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.
Details
- Vendor
- KNX Association
- Product
- KNX Protocol Connection Authorization Option 1
- Weakness
- CWE-645 (opens in a new tab)
- Status
- Analyzed
- Updated
- 16 Jul 2026
- Assigner
- ics-cert@hq.dhs.gov
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References 2
The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.
Beyond this page
Is CVE-2023-4346 in your network?
This page tells you how dangerous CVE-2023-4346 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.
CVE-2023-4346 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.
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Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.