{"id":"CVE-2026-118701","kind":"vulnerability","aliases":["CVE-2026-118701"],"related":[],"title":"Microsoft Excel: heap overflow lets a remote attacker run code","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 can be triggered over a network by an unauthenticated attacker. Successful exploitation lets the attacker execute code on the victim's machine.","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","vendor","windows"],"not_affected_if":[],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T19:19:44+00:00","first_seen_at":"2026-11-10T19:24:52+00:00","triaged_at":"2026-11-10T19:29:50+00:00","updated_at":"2026-11-10T19:29:50+00:00","category":"vendor","confidence":0.4,"triage":{"at":"2026-11-10T19:29:50Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Microsoft Excel: heap overflow lets a remote attacker run code","impact":"high","summary":"A heap-based buffer overflow in Microsoft Office Excel can be triggered over a network by an unauthenticated attacker. Successful exploitation lets the attacker execute code on the victim's machine.","audience":"everyone","category":"vendor","nicknames":[],"who_cares":["excel","microsoft-office","windows"],"confidence":0.4,"fix_status":"unknown","needs_auth":"no","worst_case":"attacker runs code on the victim's machine","analyst_note":"Check the Microsoft Security Update Guide for CVE-2026-118701 for affected builds, the patch, and whether user interaction (opening a file) is required.","how_to_check":"unknown","plain_action":"","product_name":"Microsoft Office Excel","needs_analyst":true,"not_affected_if":[],"who_is_affected":"unknown","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000645,"input_tokens":4496,"output_tokens":390,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Check the Microsoft Security Update Guide for CVE-2026-118701 for affected builds, the patch, and whether user interaction (opening a file) is required.","search":"'-118701':13A,16A '-2026':12A,15A 'allow':67C 'attack':8A,45B,50B,70C 'base':29B,60C 'buffer':30B,61C 'code':10A,52B,73C 'cve':11A,14A 'excel':2A,19A,20B,35B,66C 'execut':51B,72C 'exploit':47B 'heap':3A,28B,59C 'heap-bas':27B,58C 'let':5A,48B 'machin':57B 'microsoft':1A,17A,22B,33B,64C 'microsoft-offic':21B 'network':41B,76C 'offic':23B,34B,65C 'office':18A 'overflow':4A,31B,62C 'remot':7A 'run':9A 'success':46B 'trigger':38B 'unauthent':44B 'unauthor':69C 'vendor':24B 'victim':55B 'window':25B","nicknames":[],"mitigations":[],"who_affected":null,"tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"everyone","plain_action":null,"pkeys":["microsoftofficeexcel","officeexcel"],"ptokens":["excel","microsoft","office"],"labels":["excel","high","microsoftoffice","vendor","windows"],"campaign_type":null,"search_a":"'-118701':13A,16A '-2026':12A,15A 'attack':8A 'code':10A 'cve':11A,14A 'excel':2A,19A 'heap':3A 'let':5A 'microsoft':1A,17A 'office':18A 'overflow':4A 'remot':7A 'run':9A","search_b":"'attack':45B,50B 'base':29B 'buffer':30B 'code':52B 'excel':20B,35B 'execut':51B 'exploit':47B 'heap':28B 'heap-bas':27B 'let':48B 'machin':57B 'microsoft':22B,33B 'microsoft-offic':21B 'network':41B 'offic':23B,34B 'overflow':31B 'success':46B 'trigger':38B 'unauthent':44B 'vendor':24B 'victim':55B 'window':25B","search_c":"'allow':67C 'attack':70C 'base':60C 'buffer':61C 'code':73C 'excel':66C 'execut':72C 'heap':59C 'heap-bas':58C 'microsoft':64C 'network':76C 'offic':65C 'overflow':62C 'unauthor':69C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:19:44+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-2026-118701","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118701","severity":null,"published_at":"2026-11-10T19:19:44+00:00","modified_at":"2026-11-10T19:19:44+00:00","first_seen_at":"2026-11-10T19:24:52+00:00","fetched_at":"2026-11-10T19:24:52+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"}