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

Exploited in the wild High 7.5 Published 29 Aug 2023 Updated 16 Jul 2026

Attackers can lock KNX devices by setting a BCU key, preventing user access and requiring physical intervention to reset.

Exploited in the wild: Since 15 Jul 2026
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-4346?

CVE-2023-4346 is a high-severity denial of service vulnerability in KNX Protocol Connection Authorization Option 1, published on 29 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-645

Which versions are affected by CVE-2023-4346?

It affects 1 product.

Products include Knx Connection Authorization.

How do I fix CVE-2023-4346?

No fix has been published for CVE-2023-4346 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 29 Jul 2026.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2023-4346 being exploited?

Yes. Attackers have exploited CVE-2023-4346 in the wild since at least 15 Jul 2026.

Sources

Also known as GHSA-qccg-qqvh-pq7q.