{"id":"CVE-2026-123385","kind":"vulnerability","aliases":["CVE-2026-123385"],"related":[],"title":"Microsoft Excel: stack buffer overflow lets an attacker run code remotely","description":"Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.","summary":"A stack-based buffer overflow in Microsoft Excel can be triggered over a network by an unauthorized attacker. A successful attack 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","other","windows"],"not_affected_if":[],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T19:20:42+00:00","first_seen_at":"2026-11-10T19:25:12+00:00","triaged_at":"2026-11-10T19:26:26+00:00","updated_at":"2026-11-10T19:26:26+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-11-10T19:26:26Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Microsoft Excel: stack buffer overflow lets an attacker run code remotely","impact":"high","summary":"A stack-based buffer overflow in Microsoft Excel can be triggered over a network by an unauthorized attacker. A successful attack lets the attacker execute code on the victim's machine.","audience":"everyone","category":"other","nicknames":[],"who_cares":["microsoft-office","excel","windows"],"confidence":0.5,"fix_status":"unknown","needs_auth":"no","worst_case":"Attacker executes code on the machine over the network","analyst_note":"Find Microsoft's advisory for CVE-2026-123385 to confirm affected builds, fixed versions, and whether user interaction (opening a file) is required.","how_to_check":"unknown","plain_action":"Update Microsoft Excel through Microsoft's normal Office updates once a fix is listed for your version.","product_name":"Microsoft Office Excel","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Any computer running an affected version of Microsoft Excel may be exposed, and the sources do not say which builds are affected or what the exact trigger is. Systems that open Excel files from untrusted sources are the most likely path, but the sources do not confirm this. unknown","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000702,"input_tokens":4496,"output_tokens":504,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Find Microsoft's advisory for CVE-2026-123385 to confirm affected builds, fixed versions, and whether user interaction (opening a file) is required.","search":"'-123385':14A,17A '-2026':13A,16A 'allow':68C 'attack':8A,45B,48B,51B,71C 'base':30B,61C 'buffer':4A,31B,62C 'code':10A,53B,74C 'cve':12A,15A 'excel':2A,20A,21B,35B,67C 'execut':52B,73C 'let':6A,49B 'machin':58B 'microsoft':1A,18A,23B,34B,65C 'microsoft-offic':22B 'network':41B,77C 'offic':24B,66C 'office':19A 'overflow':5A,32B,63C 'remot':11A 'run':9A 'stack':3A,29B,60C 'stack-bas':28B,59C 'success':47B 'trigger':38B 'unauthor':44B,70C 'victim':56B 'window':26B","nicknames":[],"mitigations":[],"who_affected":"Any computer running an affected version of Microsoft Excel may be exposed, and the sources do not say which builds are affected or what the exact trigger is. Systems that open Excel files from untrusted sources are the most likely path, but the sources do not confirm this. unknown","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"everyone","plain_action":"Update Microsoft Excel through Microsoft's normal Office updates once a fix is listed for your version.","pkeys":["microsoftofficeexcel","officeexcel"],"ptokens":["excel","microsoft","office"],"labels":["excel","high","microsoftoffice","other","vendor","windows"],"campaign_type":null,"search_a":"'-123385':14A,17A '-2026':13A,16A 'attack':8A 'buffer':4A 'code':10A 'cve':12A,15A 'excel':2A,20A 'let':6A 'microsoft':1A,18A 'office':19A 'overflow':5A 'remot':11A 'run':9A 'stack':3A","search_b":"'attack':45B,48B,51B 'base':30B 'buffer':31B 'code':53B 'excel':21B,35B 'execut':52B 'let':49B 'machin':58B 'microsoft':23B,34B 'microsoft-offic':22B 'network':41B 'offic':24B 'overflow':32B 'stack':29B 'stack-bas':28B 'success':47B 'trigger':38B 'unauthor':44B 'victim':56B 'window':26B","search_c":"'allow':68C 'attack':71C 'base':61C 'buffer':62C 'code':74C 'excel':67C 'execut':73C 'microsoft':65C 'network':77C 'offic':66C 'overflow':63C 'stack':60C 'stack-bas':59C 'unauthor':70C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:20:42+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-2026-123385","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123385","severity":null,"published_at":"2026-11-10T19:20:42+00:00","modified_at":"2026-11-10T19:20:42+00:00","first_seen_at":"2026-11-10T19:25:12+00:00","fetched_at":"2026-11-10T19:25:12+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"}