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Known exploited vulnerability

CVE-2023-4346

highCVSS 3.1 7.5In CISA KEVEPSS 1.4%Published · KNX Association

The short answer

CVE-2023-4346 affects KNX Association KNX Protocol Connection Authorization Option 1 and is rated high (CVSS 7.5). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-07-15: attackers are using it, so patch it first.

What it is

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.

Severity

7.5 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploited (CISA KEV)

Yes, since Jul 15, 2026

Federal due date Jul 29, 2026

EPSS, next 30 days

1.4%

Higher than 72% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

What CISA says to do

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…

Affected products

KNX Protocol Connection Authorization Option 1. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2023-4346 being exploited?

Yes. CISA added CVE-2023-4346 to its Known Exploited Vulnerabilities catalog on 2026-07-15, with a federal remediation due date of 2026-07-29.

How do I fix CVE-2023-4346?

CISA's 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…

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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