CVE-2023-4346
Exploitation confirmed. First attested on 2026-07-15 by CISA-ADP, CISA KEV, GCVE · kevintel.
- Published2023-08-29
- WeaknessCWE-645
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTCObserved activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-4346?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-4346?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| — | all versions | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
KNX Protocol
KNX devices using Connection Authorization Option 1 Style in which no BCU Key is currently set: *
Fix
- 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 evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.due 2026-07-29
- Mitigation from the vendor CISA ICSA-23-236-01 · 1 productKNX Association recommends all system integrators, installers, ETS users, and end customers to follow common IT security guidelines. KNX Association recommends users follow the recommendations in the KNX Secure Checklist.
- Mitigation from the vendor CISA ICSA-23-236-01 · 1 productThe KNX Association also recommends developers always set the BCU Key in every KNX Project that is already finished and will be commissioned in the future. Handover the BCU Key as part of the Project Documentation to the Building Owner.
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
CISA Known Exploited Vulnerability
- Date Added
- 2026-07-15
- Patch Due Date
- 2026-07-29
- Ransomware Use
- Unknown
- 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.
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2023-08-29
- Last Modified
- 2026-07-16
- NVD status
- Analyzed
Frequently asked questions
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.