CVE-2023-4346
CVE-2023-4346 — KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability
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.
Published Updated Sources: NVD, KNX Association (CNA), CISA, FIRST EPSS, GitHub, GitHub Security Advisory
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Confirmed
CISA KEV, listed Jul 15, 2026
EPSS
1%
ahead of 57% of scored CVEs
CVSS base
7.5
high
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
Active
none · proof-of-concept · active
Automatable
Yes
can an attacker script all four kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component
Remediation
The vendor's own words where we have them.
Upgrade KNX Protocol Connection Authorization Option 1 to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
CISA 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.
Federal deadline Jul 29, 2026 — passed 30 days ago
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Treat as emergency remediation because CISA KEV status is present.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| KNX Association | KNX Protocol Connection Authorization Option 1 | 0 | Vulnerable |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Availability
High
Confidentiality
None
Integrity
None
Scope
Unchanged
Attack Complexity
Low
Attack Vector
Network
Privileges Req
None
User Interaction
None
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 7.5 | CVSS 3.1 | high | 3.9 | 3.6 | hq.dhs.gov (CNA), NVD, KNX Association (CNA), GHSA |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness & attack patterns
- CWE-645
Inferred from the weakness class — not observed against this CVE.
- T1531Account Access Removal
CISA KEV details
CISA lists a CVE here once it has evidence of exploitation against real targets.
Listed
Jul 15, 2026
Federal deadline
Jul 29, 2026
passed 30 days ago
Ransomware use
Unknown
CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.
Public exploit
Capability, not use: code existing is a different claim from anyone running it.
Repositories
16
1 of the 5 sampled are weaponized
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Prioritize edge telemetry for network-reachable KNX Protocol Connection Authorization Option 1.
- Monitor for scanner or exploit-pattern traffic after 16 public PoC repositories were reported.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 7.5 (AV:N)
Jul 16, 2026 · NVD
Added to CISA KEV catalog
Jul 15, 2026 · CISA
- 2023
Initial · CVE published
Aug 29, 2023 · NVD
Added · GHSA-qccg-qqvh-pq7q published (high)
Aug 29, 2023 · GitHub Security Advisory
References
6 on the record
- www.cisa.gov/news-events/ics-advisories/icsa-23-236-01
Third Party Advisory, US Government Resource
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346
US Government Resource
- nvd.nist.gov/vuln/detail/CVE-2023-4346
NVD, Vendor Advisory
- github.com/advisories/GHSA-qccg-qqvh-pq7q
Exploit, Third Party Advisory
- www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
US Government Resource
- www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
US Government Resource
Elsewhere on this site
- KNX Associationevery CVE for this vendor
- July 2026what else CISA listed
- Remote Code Execsame class
- CWE-645other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2023-4346 is KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism Vulnerability, a high vulnerability affecting KNX Protocol Connection Authorization Option 1 from KNX Association. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 16 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.5 describes technical severity, while EPSS 1% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.