CVE-2023-4346
HighExploitedPublic exploitKNX 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.
Published Aug 29, 2023 · Updated Jul 16, 2026
Key Facts
Patch immediately- CVE-2023-4346 is a high-severity vulnerability (CVSS 7.5 v3.1) affecting Connection Authorization (Knx), KNX Protocol Connection Authorization Option 1.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jul 15, 2026. Public exploit code is available.
- EPSS estimates a 1.3% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
1.3%
Higher than 69.8% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2023-4346 brief as a PDF
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Jul 15, 2026 | Jul 29, 2026 | Not reported |
| Industry KEV feed | Jul 15, 2026 | Jul 29, 2026 | Not reported |
| CIRCL KEV | Jul 15, 2026 | Jul 29, 2026 | Not reported |
| ENISA EUVD | Jul 15, 2026 | n/a | Not reported |
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.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Connection AuthorizationKnx | See advisory | n/a |
| KNX Protocol Connection Authorization Option 1 | See advisory | n/a |
Timeline
Publicly disclosed
Aug 29, 2023
Added to CISA KEV
Jul 15, 2026
Added to Industry KEV feed
Jul 15, 2026
Added to CIRCL KEV
Jul 15, 2026
Added to ENISA EUVD
Jul 15, 2026
Last updated
Jul 16, 2026
Weakness Type
- CWE-645 Overly Restrictive Account Lockout Mechanism
References
FAQ
Common Questions.
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.
Affected: Connection Authorization (Knx); KNX Protocol Connection Authorization Option 1. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jul 15, 2026.
Yes. It was added on Jul 15, 2026 with a federal remediation due date of Jul 29, 2026.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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