CVE-2023-4346
KNX devices that use KNX Connection Authorization and support Option 1 are, depending on the implementation, vulnerable to being locked…
- Published
- Updated
- Reserved
- Assigned by
- icscert
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability.
- Added
- 15 Jul 2026
- Fix due (US federal)
- 29 Jul 2026
- Used by ransomware
- Not known
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| icscertCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Analyzed | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.4% · top 28% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
What to do
Workaround: The KNX Association recommends users 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.
References (2)
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01 (opens in a new tab)government-resourcex_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-4346)Record last updated .