KNX Protocol Connection Authorization Option 1's Overly Restrictive Lockout Mechanism Lets Attackers Purge Devices and Lock Out Authorized Users with a BCU Key; CISA's July 29th KEV Deadline Has Passed

Last refreshed2026-09-27

Status: KEV | Advisory ID: CVE-2023-4346

Key Details

CVE	CVE-2023-4346
Vulnerability Name	KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability
Affected products	KNX Association KNX Protocol Connection Authorization Option 1
Exploitation status	Listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed active exploitation.
Classified as	CWE-645 (Overly Restrictive Account Lockout Mechanism)
KEV listing	Added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-07-15.
Exploitation prediction (EPSS)	1.29% probability of exploitation in the next 30 days (69% percentile) -- FIRST.org's EPSS model.
Federal remediation deadline	2026-07-29 (CISA KEV, Binding Operational Directive).

Affected Products, Subsystems & Sectors

Vendor	Product	Affected Versions	Patch Status
KNX Association	KNX Protocol Connection Authorization Option 1

Vendor

Product

Affected Versions

Patch Status

KNX Association

KNX Protocol Connection Authorization Option 1

Subsystems	General OT
Sectors	Multiple

What to Know

KNX Association KNX Protocol Connection Authorization Option 1 contains an overly restrictive account lockout mechanism vulnerability that could allow an attacker to purge all devices without additional security options enabled and set a BCU key to lock the device.

What to Do

Monitor KNX Association's web page for any future patch releases.

References

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2023-4346
CVE	https://www.cve.org/CVERecord?id=CVE-2023-4346

Source

Reference

NVD

https://nvd.nist.gov/vuln/detail/CVE-2023-4346

CVE

https://www.cve.org/CVERecord?id=CVE-2023-4346

KEV Required Action

Field	Value
KEV Link	https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Date Added to KEV	2026-07-15
Required Action Due Date	2026-07-29
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 evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Field

Value

KEV Link

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Date Added to KEV

2026-07-15

Required Action Due Date

2026-07-29

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 evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.