CVE-2023-4346KEV · OVERDUECWE-645

KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability

High · published August 29, 2023

Patch now

Confirmed exploited, and the score agrees

CVSS calls it high at 7.5. It is confirmed in active exploitation. It sits in the 70.1th percentile for exploit probability.

86
days past CISA
deadline
CVSS v3.1
7.5
EPSS
1%
Percentile
70.1
In the wild
Confirmed
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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.01294 · 70.1th percentile
Weakness
CWE-645 · Overly Restrictive Account Lockout Mechanism
Published
2023-08-29T19:38Z
KEV added
2026-07-15 · due 2026-07-29
EPSS history
Timeline
  • 15 JUL 00:00Z
    Added to CISA KEV — remediate by Jul 29
    kev
  • 29 AUG 19:38Z
    KNX devices that use KNX Connection Authorization and support Option 1 are, depending on the implementation, vulnerable to being locked and users being unable…
    cvelistv5