{"id":"CVE-2026-62974","kind":"vulnerability","aliases":["CVE-2026-62974"],"related":[],"title":"BACnet Stack: malformed WriteProperty request hangs server, remote denial of service","description":"BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.5, 1.5.1, and 1.6.0, a malformed but non-empty BACnet WriteProperty request can drive the official server demo into a non-terminating request-processing loop with repeated heap-backed side effects. This results in a remote unauthenticated denial of service via uncontrolled resource consumption and a non-terminating request path. This issue has been patched in versions 1.4.5, 1.5.1, and 1.6.0.","summary":"BACnet Stack is an open source BACnet protocol library in C used in embedded building-automation devices. A malformed but non-empty WriteProperty request can put the official server demo into a non-terminating loop that consumes memory, so the device stops responding.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["bacnet","building-automation","c","embedded","package"],"not_affected_if":["client-only","not-network-exposed"],"how_to_check":"- Check the BACnet Stack version your build uses; affected versions are those before `1.4.5`, `1.5.1`, and `1.6.0`.\n- Look for the official server demo or any build of this library that accepts BACnet WriteProperty requests from the network.","fix":"- Move to `1.4.5`, `1.5.1`, or `1.6.0` depending on your release line.","status":"open","published_at":"2026-11-13T16:19:29+00:00","first_seen_at":"2026-11-13T16:47:35+00:00","triaged_at":"2026-11-13T16:48:18+00:00","updated_at":"2026-11-13T16:48:18+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-13T16:48:18Z","model":"claude-haiku-5-5","output":{"fix":"- Move to `1.4.5`, `1.5.1`, or `1.6.0` depending on your release line.","reach":"network","title":"BACnet Stack: malformed WriteProperty request hangs server, remote denial of service","impact":"low","summary":"BACnet Stack is an open source BACnet protocol library in C used in embedded building-automation devices. A malformed but non-empty WriteProperty request can put the official server demo into a non-terminating loop that consumes memory, so the device stops responding.","audience":"developers","category":"package","nicknames":[],"who_cares":["bacnet","embedded","building-automation","c"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"remote attacker halts the BACnet server with resource exhaustion","analyst_note":"","how_to_check":"- Check the BACnet Stack version your build uses; affected versions are those before `1.4.5`, `1.5.1`, and `1.6.0`.\n- Look for the official server demo or any build of this library that accepts BACnet WriteProperty requests from the network.","plain_action":"","product_name":"","needs_analyst":false,"not_affected_if":["not-network-exposed","client-only"],"who_is_affected":"Teams that compile BACnet Stack into a BACnet server or device, especially the official server demo, where unauthenticated network clients can send WriteProperty requests. Systems that only use BACnet Stack as a client, or that do not expose BACnet to untrusted networks, are less exposed; the sources do not say more.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.00075,"input_tokens":4639,"output_tokens":573,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-62974':14A,17A '1.4.5':88C,150C '1.5.1':89C,151C '1.6.0':91C,153C 'autom':21B,41B 'back':120C 'bacnet':1A,18B,25B,31B,71C,75C,98C 'build':20B,40B 'building-autom':19B,39B 'c':22B,35B,80C 'consum':64B 'consumpt':135C 'cve':12A,15A 'demo':56B,106C 'denial':9A,129C 'devic':42B,68B 'drive':102C 'effect':122C 'embed':23B,38B,83C 'empti':48B,97C 'hang':6A 'heap':119C 'heap-back':118C 'issu':144C 'librari':33B,81C 'loop':62B,115C 'malform':3A,44B,93C 'memori':65B 'non':47B,60B,96C,110C,139C 'non-empti':46B,95C 'non-termin':59B,109C,138C 'offici':54B,104C 'open':29B,76C 'packag':24B 'patch':147C 'path':142C 'prior':85C 'process':114C 'protocol':32B,78C 'put':52B 'remot':8A,127C 'repeat':117C 'request':5A,50B,100C,113C,141C 'request-process':112C 'resourc':134C 'respond':70B 'result':124C 'server':7A,55B,105C 'servic':11A,131C 'side':121C 'sourc':30B,77C 'stack':2A,26B,72C,79C 'stop':69B 'system':84C 'termin':61B,111C,140C 'unauthent':128C 'uncontrol':133C 'use':36B 'version':87C,149C 'via':132C 'writeproperti':4A,49B,99C","nicknames":[],"mitigations":[],"who_affected":"Teams that compile BACnet Stack into a BACnet server or device, especially the official server demo, where unauthenticated network clients can send WriteProperty requests. Systems that only use BACnet Stack as a client, or that do not expose BACnet to untrusted networks, are less exposed; the sources do not say more.","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":"'-2026':13A,16A '-62974':14A,17A 'bacnet':1A 'cve':12A,15A 'denial':9A 'hang':6A 'malform':3A 'remot':8A 'request':5A 'server':7A 'servic':11A 'stack':2A 'writeproperti':4A","search_b":"'autom':21B,41B 'bacnet':18B,25B,31B 'build':20B,40B 'building-autom':19B,39B 'c':22B,35B 'consum':64B 'demo':56B 'devic':42B,68B 'embed':23B,38B 'empti':48B 'librari':33B 'loop':62B 'malform':44B 'memori':65B 'non':47B,60B 'non-empti':46B 'non-termin':59B 'offici':54B 'open':29B 'packag':24B 'protocol':32B 'put':52B 'request':50B 'respond':70B 'server':55B 'sourc':30B 'stack':26B 'stop':69B 'termin':61B 'use':36B 'writeproperti':49B","search_c":"'1.4.5':88C,150C '1.5.1':89C,151C '1.6.0':91C,153C 'back':120C 'bacnet':71C,75C,98C 'c':80C 'consumpt':135C 'demo':106C 'denial':129C 'drive':102C 'effect':122C 'embed':83C 'empti':97C 'heap':119C 'heap-back':118C 'issu':144C 'librari':81C 'loop':115C 'malform':93C 'non':96C,110C,139C 'non-empti':95C 'non-termin':109C,138C 'offici':104C 'open':76C 'patch':147C 'path':142C 'prior':85C 'process':114C 'protocol':78C 'remot':127C 'repeat':117C 'request':100C,113C,141C 'request-process':112C 'resourc':134C 'result':124C 'server':105C 'servic':131C 'side':121C 'sourc':77C 'stack':72C,79C 'system':84C 'termin':111C,140C 'unauthent':128C 'uncontrol':133C 'version':87C,149C 'via':132C 'writeproperti':99C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-07-16T13:17:57+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-2026-62974","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-62974","severity":null,"published_at":"2026-11-13T16:19:29+00:00","modified_at":"2026-11-13T16:19:29+00:00","first_seen_at":"2026-11-13T16:47:35+00:00","fetched_at":"2026-11-13T16:47:35+00:00","note":null}],"documents":[{"id":147675,"url":"https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-2c8x-f46r-8phh","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-07-16T13:17:57+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"}