CVEs / CVE-2023-4346
CVE-2023-4346: KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability
- Known exploited in the CISA KEV catalog since 15 Jul 2026
- high 7.5 CVSS 3.1 (NVD)
- EPSS 1.36% chance of exploitation in the next 30 days, higher than 71% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| KNX Association KNX Protocol Connection Authorization Option 1 | all versions | — |
Exploitation
| In CISA KEV since | 15 Jul 2026 |
|---|---|
| Due date for US federal agencies | 29 Jul 2026 |
| Used in ransomware campaigns | 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. |
Severity
| CVSS 3.1 | 7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HScored by NVD |
|---|---|
| Weakness | CWE-645 |
References
- CVE-2023-4346 on NVD
- CVE-2023-4346 in the CISA KEV catalog
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01 Third Party Advisory, US Government Resource
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.