---
id: "CVE-2023-4346"
kind: "vulnerability"
aliases: ["CVE-2023-4346"]
title: "KNX devices that use KNX Connection Authorization and support Option 1 are, depending on the implementation,\u2026"
severity: "high"
cvss: 7.5
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "KNX Association KNX Protocol Connection Authorization Option 1", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "knx connection authorization", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["building-automation", "exploited", "infrastructure", "ip-gateways", "knx"]
not_affected_if: ["knx-security-enabled", "no-knx-devices"]
published_at: "2023-08-29T20:15:10+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T23:44:51+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-4346", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-4346", "first_seen_at": "2026-10-23T23:44:51+00:00"}]
---

# KNX devices that use KNX Connection Authorization and support Option 1 are, depending on the implementation,…

KNX building-automation devices use an overly restrictive account lockout in their connection authorization, which lets an attacker purge all devices and set a BCU key that locks the device. CISA lists it as actively exploited in the wild.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:KNX Association KNX Protocol Connection Authorization Option 1 affected ? fixed ?
- vendor:knx connection authorization affected ? fixed ?

## Fix

Apply the vendor mitigation from KNX Association; CISA's KEV entry says to follow vendor instructions and discontinue use if no mitigation is available.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-4346
- 2026-10-23T23:44:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2023-4346

## From the sources

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.

CISA 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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_