What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2026-07-15
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-08-29 · updated 2026-07-16
• Weakness: 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.

Affected products

• KNX Association KNX Protocol Connection Authorization Option 1: all versions

References

• https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01
• https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346

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