{"id":"CVE-2026-104204","kind":"vulnerability","aliases":["CVE-2026-104204"],"related":[],"title":"BACnet Stack: Structured View flaw lets a server be knocked offline","description":"BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to version 1.6.1, there is a server-side denial-of-service issue affecting the Structured View object implementation. This issue has been patched in versions 1.6.1 and 1.7.0.","summary":"BACnet Stack is a C library for building BACnet building-automation devices. Before version 1.6.1, a crafted request to the Structured View object implementation can crash or stall the server, causing denial of service.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["bacnet","building-automation","c","embedded","package"],"not_affected_if":["no-bacnet-server","structured-view-disabled"],"how_to_check":"- Check the BACnet Stack version in your build or vendored sources, for example `grep -i version` on the library's version header.\n- Confirm whether your device or application enables the Structured View object.","fix":"- BACnet Stack: upgrade to `1.6.1` or `1.7.0`.","status":"open","published_at":"2026-11-13T19:17:37+00:00","first_seen_at":"2026-11-13T19:52:09+00:00","triaged_at":"2026-11-13T19:54:04+00:00","updated_at":"2026-11-13T19:54:04+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-13T19:54:04Z","model":"claude-haiku-5-5","output":{"fix":"- BACnet Stack: upgrade to `1.6.1` or `1.7.0`.","reach":"network","title":"BACnet Stack: Structured View flaw lets a server be knocked offline","impact":"low","summary":"BACnet Stack is a C library for building BACnet building-automation devices. Before version 1.6.1, a crafted request to the Structured View object implementation can crash or stall the server, causing denial of service.","audience":"developers","category":"package","nicknames":[],"who_cares":["bacnet","embedded","building-automation","c"],"confidence":0.6,"fix_status":"available","needs_auth":"unknown","worst_case":"server crashes or stops responding to requests","analyst_note":"","how_to_check":"- Check the BACnet Stack version in your build or vendored sources, for example `grep -i version` on the library's version header.\n- Confirm whether your device or application enables the Structured View object.","plain_action":"","product_name":"","needs_analyst":false,"not_affected_if":["no-bacnet-server","structured-view-disabled"],"who_is_affected":"Systems built on BACnet Stack before 1.6.1 that expose the BACnet server, including embedded building-automation devices that use the Structured View object. Applications that do not run a BACnet server or do not use Structured View are less exposed. Whether a remote network peer can reach the server is not stated in the sources.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000715,"input_tokens":4551,"output_tokens":520,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-104204':14A,17A '-2026':13A,16A '1.6.1':40B,77C,102C '1.7.0':104C 'affect':89C 'autom':21B,36B 'bacnet':1A,18B,25B,33B,60C,64C 'build':20B,32B,35B 'building-autom':19B,34B 'c':22B,29B,69C 'caus':56B 'craft':42B 'crash':51B 'cve':12A,15A 'denial':57B,85C 'denial-of-servic':84C 'devic':37B 'embed':23B,72C 'flaw':5A 'implement':49B,94C 'issu':88C,96C 'knock':10A 'let':6A 'librari':30B,70C 'object':48B,93C 'offlin':11A 'open':65C 'packag':24B 'patch':99C 'prior':74C 'protocol':67C 'request':43B 'server':8A,55B,82C 'server-sid':81C 'servic':59B,87C 'side':83C 'sourc':66C 'stack':2A,26B,61C,68C 'stall':53B 'structur':3A,46B,91C 'system':73C 'version':39B,76C,101C 'view':4A,47B,92C","nicknames":[],"mitigations":[],"who_affected":"Systems built on BACnet Stack before 1.6.1 that expose the BACnet server, including embedded building-automation devices that use the Structured View object. Applications that do not run a BACnet server or do not use Structured View are less exposed. Whether a remote network peer can reach the server is not stated in the sources.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["bacnet","buildingautomation","c","embedded","high","package"],"campaign_type":null,"search_a":"'-104204':14A,17A '-2026':13A,16A 'bacnet':1A 'cve':12A,15A 'flaw':5A 'knock':10A 'let':6A 'offlin':11A 'server':8A 'stack':2A 'structur':3A 'view':4A","search_b":"'1.6.1':40B 'autom':21B,36B 'bacnet':18B,25B,33B 'build':20B,32B,35B 'building-autom':19B,34B 'c':22B,29B 'caus':56B 'craft':42B 'crash':51B 'denial':57B 'devic':37B 'embed':23B 'implement':49B 'librari':30B 'object':48B 'packag':24B 'request':43B 'server':55B 'servic':59B 'stack':26B 'stall':53B 'structur':46B 'version':39B 'view':47B","search_c":"'1.6.1':77C,102C '1.7.0':104C 'affect':89C 'bacnet':60C,64C 'c':69C 'denial':85C 'denial-of-servic':84C 'embed':72C 'implement':94C 'issu':88C,96C 'librari':70C 'object':93C 'open':65C 'patch':99C 'prior':74C 'protocol':67C 'server':82C 'server-sid':81C 'servic':87C 'side':83C 'sourc':66C 'stack':61C,68C 'structur':91C 'system':73C 'version':76C,101C 'view':92C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-10-04T10:41:00+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-104204","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-104204","severity":null,"published_at":"2026-11-13T19:17:37+00:00","modified_at":"2026-11-13T19:17:37+00:00","first_seen_at":"2026-11-13T19:52:09+00:00","fetched_at":"2026-11-13T19:52:09+00:00","note":null}],"documents":[{"id":149128,"url":"https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-hg85-pmm3-jfcf","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-04T10:41:00+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}