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CVE-2023-4346

HIGH 7.5 KNOWN EXPLOITED ALL-YEARS

Published 2023-08-29 · Last modified 2026-07-16 · icscert · NVD: Analyzed

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.

ACTIVELY EXPLOITED

Confirmed exploited in the wild — in CISA KEV since 2026-07-15. Patch or mitigate now.

Exploitation likelihood

1.4%chance of exploitation in 30 days · 72nd percentile

● In CISA KEV (2026-07-15)○ Catalogued PoC◆ SSVC: exploitation active, automatable yes

Impact if exploited

7.5CVSS 3.1 · HIGH · CNA

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Knx Association Knx

Products Knx Protocol Connection Authorization Option 1 Connection Authorization

Weakness (CWE)

  • CWE-645: Overly Restrictive Account Lockout Mechanism

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References and research data (JSON)

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

  • VulnCheck KEV · 2026-07-15T00:00:00Z

    Source guidance: 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.

    Source ransomware assessment: Unknown

    VulnCheck KEV · CVE-2023-4346 · Updated 2026-07-15T00:00:00Z
  • VulnCheck KEV · 2026-07-15T00:00:00ZVulnCheck KEV · CVE-2023-4346
    VulnCheck KEV · CVE-2023-4346
  • VulnCheck KEV · 2026-08-07T00:00:00ZVulnCheck KEV · CVE-2023-4346

Known Affected Software Configurations

VendorProductVersion range
KnxConnection Authorization*

All CVSS metrics

  • HIGH 7.5 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  • HIGH 7.5 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS