{"id":"CVE-2026-118726","kind":"vulnerability","aliases":["CVE-2026-118726"],"related":[],"title":"Microsoft Excel: heap overflow lets an attacker run code over a network","description":"Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.","summary":"A heap-based buffer overflow in Microsoft Office Excel lets an unauthenticated attacker run code on a victim's machine over the network. The sources give no further detail on the trigger or the affected Excel builds.","severity":"high","cvss":8.8,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"Microsoft Office Excel","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["excel","microsoft-office","package","windows"],"not_affected_if":[],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T19:19:48+00:00","first_seen_at":"2026-11-10T19:24:54+00:00","triaged_at":"2026-11-10T19:28:15+00:00","updated_at":"2026-11-10T19:28:15+00:00","category":"package","confidence":0.5,"triage":{"at":"2026-11-10T19:28:15Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Microsoft Excel: heap overflow lets an attacker run code over a network","impact":"high","summary":"A heap-based buffer overflow in Microsoft Office Excel lets an unauthenticated attacker run code on a victim's machine over the network. The sources give no further detail on the trigger or the affected Excel builds.","audience":"everyone","category":"package","nicknames":[],"who_cares":["excel","microsoft-office","windows"],"confidence":0.5,"fix_status":"unknown","needs_auth":"no","worst_case":"Attacker runs code on the victim's machine over the network","analyst_note":"Find the Microsoft Security Response Center advisory for CVE-2026-118726 to get affected builds, fixed versions and whether user interaction is needed.","how_to_check":"- unknown","plain_action":"Update Microsoft Excel through Microsoft Update once Microsoft publishes the fix.","product_name":"Microsoft Office Excel","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Anyone running Microsoft Office Excel on an affected build may be exposed, as the sources describe a network-reachable attack without credentials. The sources do not list affected versions or whether Office for the web or Mac is included. unknown","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.0007,"input_tokens":4496,"output_tokens":500,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Find the Microsoft Security Response Center advisory for CVE-2026-118726 to get affected builds, fixed versions and whether user interaction is needed.","search":"'-118726':15A,18A '-2026':14A,17A 'affect':63B 'allow':75C 'attack':7A,41B,78C 'base':31B,68C 'buffer':32B,69C 'build':65B 'code':9A,43B,81C 'cve':13A,16A 'detail':57B 'excel':2A,21A,22B,37B,64B,74C 'execut':80C 'give':54B 'heap':3A,30B,67C 'heap-bas':29B,66C 'let':5A,38B 'machin':48B 'microsoft':1A,19A,24B,35B,72C 'microsoft-offic':23B 'network':12A,51B,84C 'offic':25B,36B,73C 'office':20A 'overflow':4A,33B,70C 'packag':26B 'run':8A,42B 'sourc':53B 'trigger':60B 'unauthent':40B 'unauthor':77C 'victim':46B 'window':27B","nicknames":[],"mitigations":[],"who_affected":"Anyone running Microsoft Office Excel on an affected build may be exposed, as the sources describe a network-reachable attack without credentials. The sources do not list affected versions or whether Office for the web or Mac is included. unknown","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"everyone","plain_action":"Update Microsoft Excel through Microsoft Update once Microsoft publishes the fix.","pkeys":["microsoftofficeexcel","officeexcel"],"ptokens":["excel","microsoft","office"],"labels":["excel","high","microsoftoffice","package","vendor","windows"],"campaign_type":null,"search_a":"'-118726':15A,18A '-2026':14A,17A 'attack':7A 'code':9A 'cve':13A,16A 'excel':2A,21A 'heap':3A 'let':5A 'microsoft':1A,19A 'network':12A 'office':20A 'overflow':4A 'run':8A","search_b":"'affect':63B 'attack':41B 'base':31B 'buffer':32B 'build':65B 'code':43B 'detail':57B 'excel':22B,37B,64B 'give':54B 'heap':30B 'heap-bas':29B 'let':38B 'machin':48B 'microsoft':24B,35B 'microsoft-offic':23B 'network':51B 'offic':25B,36B 'overflow':33B 'packag':26B 'run':42B 'sourc':53B 'trigger':60B 'unauthent':40B 'victim':46B 'window':27B","search_c":"'allow':75C 'attack':78C 'base':68C 'buffer':69C 'code':81C 'excel':74C 'execut':80C 'heap':67C 'heap-bas':66C 'microsoft':72C 'network':84C 'offic':73C 'overflow':70C 'unauthor':77C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:19:48+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-2026-118726","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118726","severity":null,"published_at":"2026-11-10T19:19:48+00:00","modified_at":"2026-11-10T19:19:48+00:00","first_seen_at":"2026-11-10T19:24:54+00:00","fetched_at":"2026-11-10T19:24:54+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"}