{"id":"CVE-2026-118294","kind":"vulnerability","aliases":["CVE-2026-118294"],"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 lets an unauthorized attacker run code over a network. The sources give no further detail on how the file or request is delivered.","severity":"high","cvss":8.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["excel","microsoft-office","other","windows"],"not_affected_if":[],"how_to_check":"- Check the installed Excel build under File > Account > About Excel in Microsoft Office.","fix":null,"status":"open","published_at":"2026-11-10T19:19:42+00:00","first_seen_at":"2026-11-10T19:24:51+00:00","triaged_at":"2026-11-10T19:29:57+00:00","updated_at":"2026-11-10T19:29:57+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-11-10T19:29:57Z","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 lets an unauthorized attacker run code over a network. The sources give no further detail on how the file or request is delivered.","audience":"businesses","category":"other","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 update guide entry for CVE-2026-118294 to confirm affected builds, fixed versions and whether user interaction is needed.","how_to_check":"- Check the installed Excel build under File > Account > About Excel in Microsoft Office.\n- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Organizations running Microsoft Office Excel. The sources do not state which Excel builds or configurations are affected, or whether opening a file is required.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000664,"input_tokens":4496,"output_tokens":429,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Find the Microsoft security update guide entry for CVE-2026-118294 to confirm affected builds, fixed versions and whether user interaction is needed.","search":"'-118294':13A,16A '-2026':12A,15A 'allow':65C 'attack':8A,36B,68C 'base':26B,58C 'buffer':27B,59C 'code':10A,38B,71C 'cve':11A,14A 'deliv':55B 'detail':47B 'excel':2A,17B,32B,64C 'execut':70C 'file':51B 'give':44B 'heap':3A,25B,57C 'heap-bas':24B,56C 'let':5A,33B 'microsoft':1A,19B,30B,62C 'microsoft-offic':18B 'network':41B,74C 'offic':20B,31B,63C 'overflow':4A,28B,60C 'remot':7A 'request':53B 'run':9A,37B 'sourc':43B 'unauthor':35B,67C 'window':22B","nicknames":[],"mitigations":[],"who_affected":"Organizations running Microsoft Office Excel. The sources do not state which Excel builds or configurations are affected, or whether opening a file is required.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["excel","high","microsoftoffice","other","windows"],"campaign_type":null,"search_a":"'-118294':13A,16A '-2026':12A,15A 'attack':8A 'code':10A 'cve':11A,14A 'excel':2A 'heap':3A 'let':5A 'microsoft':1A 'overflow':4A 'remot':7A 'run':9A","search_b":"'attack':36B 'base':26B 'buffer':27B 'code':38B 'deliv':55B 'detail':47B 'excel':17B,32B 'file':51B 'give':44B 'heap':25B 'heap-bas':24B 'let':33B 'microsoft':19B,30B 'microsoft-offic':18B 'network':41B 'offic':20B,31B 'overflow':28B 'request':53B 'run':37B 'sourc':43B 'unauthor':35B 'window':22B","search_c":"'allow':65C 'attack':68C 'base':58C 'buffer':59C 'code':71C 'excel':64C 'execut':70C 'heap':57C 'heap-bas':56C 'microsoft':62C 'network':74C 'offic':63C 'overflow':60C 'unauthor':67C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:19:42+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-2026-118294","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118294","severity":null,"published_at":"2026-11-10T19:19:42+00:00","modified_at":"2026-11-10T19:19:42+00:00","first_seen_at":"2026-11-10T19:24:51+00:00","fetched_at":"2026-11-10T19:24:51+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"}