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CVE-2023-4346: KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability
CVE-2023-4346: high vulnerability affecting KNX Protocol Connection Authorization Option 1. Check CVSS, KEV status, business impact and recommended.
- CVSS
- 7.5 HIGH
- EPSS
- 56.18%
- Known exploited
- yes
- Product
- KNX Protocol Connection Authorization Option 1
What is known
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.
Business impact
Successful exploitation of CVE-2023-4346, a high vulnerability (CVSS 7.5) affecting KNX Protocol Connection Authorization Option 1, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration. CISA lists this vulnerability in the Known Exploited Vulnerabilities catalog, so exposed systems should be treated as a priority.
Recommended administrator action
Confirm whether KNX Protocol Connection Authorization Option 1 is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. Where applicable, include the CISA KEV remediation due date of 2026-07-29 in the change plan. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.