{"id":"CVE-2026-118714","kind":"vulnerability","aliases":["CVE-2026-118714"],"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 attacker send a crafted input over the network to run code. The sources give no details on the exact file format or trigger path.","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 the MSRC Update Guide entry for CVE-2026-118714 and compare your Office/Excel build (File > Account > About Excel) with the fixed build listed there. Until you have confirmed it, treat any Excel on Windows as possibly exposed and apply the current Office updates.","fix":null,"status":"open","published_at":"2026-11-10T19:19:46+00:00","first_seen_at":"2026-11-10T19:24:53+00:00","triaged_at":"2026-11-10T19:28:25+00:00","updated_at":"2026-11-10T23:06:12+00:00","category":"other","confidence":0.4,"triage":{"at":"2026-11-10T19:28:25Z","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 attacker send a crafted input over the network to run code. The sources give no details on the exact file format or trigger path.","audience":"businesses","category":"other","nicknames":[],"who_cares":["excel","microsoft-office","windows"],"confidence":0.4,"fix_status":"unknown","needs_auth":"no","worst_case":"Attacker runs arbitrary code on the affected machine over the network","analyst_note":"Find the Microsoft security update guide entry for CVE-2026-118714 to confirm affected builds, fixed versions and whether user interaction (opening a file) is required.","how_to_check":"- Check the installed Excel build under File > Account > About Excel in Microsoft 365 or Office.\n- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Organizations running Microsoft Office Excel are potentially exposed, since the attack is reachable over the network without authentication according to the NVD description. The sources do not say which Excel builds or file types are affected, so unknown.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000683,"input_tokens":4496,"output_tokens":467,"severity_before":"high"},"analyst_status":"done","analyst_note":"Find the Microsoft security update guide entry for CVE-2026-118714 to confirm affected builds, fixed versions and whether user interaction (opening a file) is required.","search":"'-118714':14A,17A '-2026':13A,16A 'allow':68C 'attack':9A,35B,71C 'base':27B,61C 'buffer':4A,28B,62C 'code':11A,45B,74C 'craft':38B 'cve':12A,15A 'detail':50B 'exact':53B 'excel':2A,18B,32B,67C 'execut':73C 'file':54B 'format':55B 'give':48B 'heap':3A,26B,60C 'heap-bas':25B,59C 'input':39B 'let':6A,33B 'microsoft':1A,20B,31B,65C 'microsoft-offic':19B 'network':42B,77C 'offic':21B,66C 'overflow':5A,29B,63C 'path':58B 'remot':8A 'run':10A,44B 'send':36B 'sourc':47B 'trigger':57B 'unauthor':70C 'window':23B","nicknames":[],"mitigations":[],"who_affected":"NVD scores this as network-reachable code execution that needs user interaction (CVSS UI:R), so an attacker would probably need someone to open a crafted Excel file or input. Affected Excel builds and fixed versions are not confirmed yet. Systems without Microsoft Excel can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"unknown","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["excel","high","microsoftoffice","other","windows"],"campaign_type":null,"search_a":"'-118714':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":"'attack':35B 'base':27B 'buffer':28B 'code':45B 'craft':38B 'detail':50B 'exact':53B 'excel':18B,32B 'file':54B 'format':55B 'give':48B 'heap':26B 'heap-bas':25B 'input':39B 'let':33B 'microsoft':20B,31B 'microsoft-offic':19B 'network':42B 'offic':21B 'overflow':29B 'path':58B 'run':44B 'send':36B 'sourc':47B 'trigger':57B 'window':23B","search_c":"'allow':68C 'attack':71C 'base':61C 'buffer':62C 'code':74C 'excel':67C 'execut':73C 'heap':60C 'heap-bas':59C 'microsoft':65C 'network':77C 'offic':66C 'overflow':63C 'unauthor':70C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:19:46+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-2026-118714","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118714","severity":null,"published_at":"2026-11-10T19:19:46+00:00","modified_at":"2026-11-10T19:19:47+00:00","first_seen_at":"2026-11-10T19:24:53+00:00","fetched_at":"2026-11-10T19:24:53+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-118714:3103","url":null,"severity":null,"published_at":"2026-11-10T23:06:12+00:00","modified_at":"2026-11-10T23:06:12+00:00","first_seen_at":"2026-11-10T23:06:12+00:00","fetched_at":"2026-11-10T23:06:12+00:00","note":"Could not read the MSRC Update Guide entry: the page is JavaScript-only, the CVRF feed was too large to fetch, browser-cli returned 402 (no minutes). Only NVD is known (CVSS 8.8, UI:R, so a user must open a crafted file or input). No builds, fix or KB confirmed; nothing verified. Revisit when MSRC text is readable."}],"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"}