{"id":"CVE-2023-4346","published":"2023-08-29T20:15:10Z","modified":"2026-07-16T05:16:16Z","title":"KNX Association KNX Protocol Connection Authorization Option 1 Overly Restrictive Account Lockout Mechanism…","vendor":"KNX Association","product":"KNX Protocol Connection Authorization Option 1","tier":"core","eol":null,"description":{"text":"\nKNX 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. \n\n","provenance":"source","from":"NVD"},"summary":null,"cvss":{"score":7.5,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.01363,"percentile":0.71715,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2026-07-15","dueDate":"2026-07-29","ransomware":false,"requiredAction":"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.","notes":"https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2023-4346","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-07-15","exploitedFirstSeen":"2026-07-15","ransomware":false,"evidence":[{"url":"https://previdian.com/CVE-2023-4346","date":"2026-07-15"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-07-15"},{"url":"https://www.recordedfuture.com/blog/july-2026-cve-landscape","date":"2026-08-07"}],"evidenceTotal":3,"provenance":"source"},"exploited":true,"otx":{"pulseCount":30,"pulses":[{"name":"Actively_Exploited_Kev | Oct 30, 2026","url":"https://otx.alienvault.com/pulse/6ae35d889ea92b4ce19c2680","created":"2026-10-29"},{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"}],"provenance":"machine"},"cwes":[{"id":"CWE-645","name":"Overly Restrictive Account Lockout Mechanism"}],"references":[{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01","tags":["Third Party Advisory","US Government Resource"]},{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-23-236-01","tags":["Third Party Advisory","US Government Resource"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: network-reachable attacker interfaces the installation","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"an attacker with access to that network could interface with the KNX installation","start":425,"end":506}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1499.004","name":"Application or System Exploitation","tactics":["impact"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: locks device, denying legitimate access","mappingType":"primary_impact","evidence":[{"from":"description","quote":"purge all devices without additional security options enabled, and set a BCU key, locking the device","start":508,"end":608}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2023-54211","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-54211","exploited":true,"exploitedSince":"2026-07-15","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1499.004"],"provenance":"ai"}],"timeline":[{"date":"2023-08-29","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-4346","provenance":"source"},{"date":"2026-07-15","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://previdian.com/CVE-2023-4346","provenance":"source"},{"date":"2026-07-15","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2026-07-15","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-54211","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":1051},"priority":{"score":62.6,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":5.0,"detail":"added 107 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":14.34,"detail":"percentile 0.7171"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"30 pulses"},{"name":"CVSS severity","points":5.25,"detail":"base score 7.5"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}