{"id":"CVE-2026-124176","kind":"vulnerability","aliases":["CVE-2026-124176"],"related":[],"title":"Microsoft Excel: heap buffer 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 Excel lets an unauthorized attacker trigger memory corruption over a network. The sources say an attacker could execute code on the affected machine.","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":"- Open Excel and check the version under File > Account (or About Excel) against Microsoft's security update notes","fix":null,"status":"open","published_at":"2026-11-10T19:20:45+00:00","first_seen_at":"2026-11-10T19:25:13+00:00","triaged_at":"2026-11-10T19:26:19+00:00","updated_at":"2026-11-10T19:26:19+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-11-10T19:26:19Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Microsoft Excel: heap buffer overflow lets a remote attacker run code","impact":"high","summary":"A heap-based buffer overflow in Microsoft Excel lets an unauthorized attacker trigger memory corruption over a network. The sources say an attacker could execute code on the affected machine.","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 machine remotely","analyst_note":"Find the affected Excel builds and fixed versions in Microsoft's CVE-2026-124176 update guide; check whether user interaction (opening a file) is required.","how_to_check":"- Open Excel and check the version under File > Account (or About Excel) against Microsoft's security update notes\n- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Organizations running Microsoft Office Excel. The sources do not list affected Excel build numbers or whether opening a file is required, so the exposure window is unknown.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000672,"input_tokens":4496,"output_tokens":444,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Find the affected Excel builds and fixed versions in Microsoft's CVE-2026-124176 update guide; check whether user interaction (opening a file) is required.","search":"'-124176':14A,17A '-2026':13A,16A 'affect':53B 'allow':64C 'attack':9A,36B,47B,67C 'base':27B,57C 'buffer':4A,28B,58C 'code':11A,50B,70C 'corrupt':39B 'could':48B 'cve':12A,15A 'excel':2A,18B,32B,63C 'execut':49B,69C 'heap':3A,26B,56C 'heap-bas':25B,55C 'let':6A,33B 'machin':54B 'memori':38B 'microsoft':1A,20B,31B,61C 'microsoft-offic':19B 'network':42B,73C 'offic':21B,62C 'overflow':5A,29B,59C 'remot':8A 'run':10A 'say':45B 'sourc':44B 'trigger':37B 'unauthor':35B,66C 'window':23B","nicknames":[],"mitigations":[],"who_affected":"Organizations running Microsoft Office Excel. The sources do not list affected Excel build numbers or whether opening a file is required, so the exposure window is unknown.","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":"'-124176':14A,17A '-2026':13A,16A 'attack':9A 'buffer':4A 'code':11A 'cve':12A,15A 'excel':2A 'heap':3A 'let':6A 'microsoft':1A 'overflow':5A 'remot':8A 'run':10A","search_b":"'affect':53B 'attack':36B,47B 'base':27B 'buffer':28B 'code':50B 'corrupt':39B 'could':48B 'excel':18B,32B 'execut':49B 'heap':26B 'heap-bas':25B 'let':33B 'machin':54B 'memori':38B 'microsoft':20B,31B 'microsoft-offic':19B 'network':42B 'offic':21B 'overflow':29B 'say':45B 'sourc':44B 'trigger':37B 'unauthor':35B 'window':23B","search_c":"'allow':64C 'attack':67C 'base':57C 'buffer':58C 'code':70C 'excel':63C 'execut':69C 'heap':56C 'heap-bas':55C 'microsoft':61C 'network':73C 'offic':62C 'overflow':59C 'unauthor':66C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:20:45+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-2026-124176","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-124176","severity":null,"published_at":"2026-11-10T19:20:45+00:00","modified_at":"2026-11-10T19:20:45+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"}