{"id":"CVE-2026-123394","kind":"vulnerability","aliases":["CVE-2026-123394"],"related":[],"title":"Microsoft Word: heap buffer overflow lets a remote attacker run code","description":"Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network.","summary":"A heap-based buffer overflow in Microsoft Office Word lets an unauthorized attacker run code over a network. The sources give no further detail on the trigger or the affected Word versions.","severity":"high","cvss":8.8,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"Microsoft Office Word","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["microsoft-office","other","windows","word"],"not_affected_if":[],"how_to_check":"- Check the installed Word version in File > Account > About Word.","fix":null,"status":"open","published_at":"2026-11-10T19:20:43+00:00","first_seen_at":"2026-11-10T19:25:13+00:00","triaged_at":"2026-11-10T19:26:18+00:00","updated_at":"2026-11-10T19:26:18+00:00","category":"other","confidence":0.4,"triage":{"at":"2026-11-10T19:26:18Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Microsoft Word: heap buffer overflow lets a remote attacker run code","impact":"high","summary":"A heap-based buffer overflow in Microsoft Office Word lets an unauthorized attacker run code over a network. The sources give no further detail on the trigger or the affected Word versions.","audience":"businesses","category":"other","nicknames":[],"who_cares":["microsoft-office","word","windows"],"confidence":0.4,"fix_status":"unknown","needs_auth":"no","worst_case":"Attacker runs arbitrary code on the victim's machine over the network.","analyst_note":"Find the Microsoft advisory for CVE-2026-123394 to confirm affected Word builds, the fixed update, and whether user interaction (opening a document) is required.","how_to_check":"- Check the installed Word version in File > Account > About Word.\n- unknown","plain_action":"","product_name":"Microsoft Office Word","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Organizations running Microsoft Office Word are the likely affected party, since the flaw is in Word itself. The sources do not name the affected builds or whether opening a file is enough to trigger it.","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000687,"input_tokens":4494,"output_tokens":475,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Find the Microsoft advisory for CVE-2026-123394 to confirm affected Word builds, the fixed update, and whether user interaction (opening a document) is required.","search":"'-123394':14A,17A '-2026':13A,16A 'affect':57B 'allow':69C 'attack':9A,40B,72C 'base':30B,62C 'buffer':4A,31B,63C 'code':11A,42B,75C 'cve':12A,15A 'detail':51B 'execut':74C 'give':48B 'heap':3A,29B,61C 'heap-bas':28B,60C 'let':6A,37B 'microsoft':1A,18A,22B,34B,66C 'microsoft-offic':21B 'network':45B,78C 'offic':23B,35B,67C 'office':19A 'overflow':5A,32B,64C 'remot':8A 'run':10A,41B 'sourc':47B 'trigger':54B 'unauthor':39B,71C 'version':59B 'window':25B 'word':2A,20A,26B,36B,58B,68C","nicknames":[],"mitigations":[],"who_affected":"Organizations running Microsoft Office Word are the likely affected party, since the flaw is in Word itself. The sources do not name the affected builds or whether opening a file is enough to trigger it.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":["microsoftofficeword","officeword"],"ptokens":["microsoft","office","word"],"labels":["high","microsoftoffice","other","vendor","windows","word"],"campaign_type":null,"search_a":"'-123394':14A,17A '-2026':13A,16A 'attack':9A 'buffer':4A 'code':11A 'cve':12A,15A 'heap':3A 'let':6A 'microsoft':1A,18A 'office':19A 'overflow':5A 'remot':8A 'run':10A 'word':2A,20A","search_b":"'affect':57B 'attack':40B 'base':30B 'buffer':31B 'code':42B 'detail':51B 'give':48B 'heap':29B 'heap-bas':28B 'let':37B 'microsoft':22B,34B 'microsoft-offic':21B 'network':45B 'offic':23B,35B 'overflow':32B 'run':41B 'sourc':47B 'trigger':54B 'unauthor':39B 'version':59B 'window':25B 'word':26B,36B,58B","search_c":"'allow':69C 'attack':72C 'base':62C 'buffer':63C 'code':75C 'execut':74C 'heap':61C 'heap-bas':60C 'microsoft':66C 'network':78C 'offic':67C 'overflow':64C 'unauthor':71C 'word':68C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:20:43+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-123394","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123394","severity":null,"published_at":"2026-11-10T19:20:43+00:00","modified_at":"2026-11-10T19:20:43+00:00","first_seen_at":"2026-11-10T19:25:13+00:00","fetched_at":"2026-11-10T19:25:13+00:00","note":null}],"documents":[],"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"}