CVE-2023-4346: KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
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.
Description quoted from the CVE record (assigned by icscert, published 2023-08-29).
Weakness: CWE-645 Overly Restrictive Account Lockout Mechanism
How it can be exploited
Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality none, integrity none, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: partial.
- On CISA KEV since
- 2026-07-15
- US federal deadline
- 2026-07-29
- Ransomware use
- Not known
Public exploit evidence (Exploit Observer)
Also known as: CNNVD-202308-2065, EUVD-2023-54211, GHSA-qccg-qqvh-pq7q
Exploit Observer has no public exploit code that names this CVE or one of its aliases.
Vulnerability databases and vendor advisories (5)
Catalogue entries, not exploit evidence.
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2023-54211
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-qccg-qqvh-pq7q
- Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2023-4346
- Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346
- Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202308-2065
10 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.
VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.
Live scores
- EPSS
- 0.014
some chance of attack soon - VEDAS
- 0.518
some exploit evidence - On CISA KEV
- Yes, since 2026-07-15
- Detection rule
- None yet
Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| KNX Association KNX Protocol Connection Authorization Option 1 | version 0 | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
Exploit Observer also maps it to: knx connection_authorization.
How to fix it
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.
Vendor guidance:
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2023-4346
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Government sources
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01 (government-resource)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346 (government-resource)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.