{"id":"CVE-2026-123376","kind":"vulnerability","aliases":["CVE-2026-123376"],"related":[],"title":"Microsoft Outlook: heap buffer overflow lets an attacker run code remotely","description":"Heap-based buffer overflow in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.","summary":"A heap-based buffer overflow in Microsoft Office Outlook can be triggered over a network by an unauthorized attacker. A successful attack lets the attacker execute code on the affected machine.","severity":"high","cvss":8.8,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"Microsoft Office Outlook","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["microsoft-office","other","outlook","windows"],"not_affected_if":[],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T19:20:40+00:00","first_seen_at":"2026-11-10T19:25:12+00:00","triaged_at":"2026-11-10T19:27:40+00:00","updated_at":"2026-11-10T19:27:40+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-11-10T19:27:40Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Microsoft Outlook: heap buffer overflow lets an attacker run code remotely","impact":"high","summary":"A heap-based buffer overflow in Microsoft Office Outlook can be triggered over a network by an unauthorized attacker. A successful attack lets the attacker execute code on the affected machine.","audience":"everyone","category":"other","nicknames":[],"who_cares":["outlook","microsoft-office","windows"],"confidence":0.5,"fix_status":"unknown","needs_auth":"no","worst_case":"Attacker runs code on the machine over the network.","analyst_note":"Check the Microsoft Security Response Center advisory for CVE-2026-123376 for affected builds, whether user interaction is needed, and the patch.","how_to_check":"unknown","plain_action":"Update Microsoft Outlook to the latest version through Microsoft Update once Microsoft releases a fix.","product_name":"Microsoft Office Outlook","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Machines running Microsoft Office Outlook. The sources do not say which Outlook builds or configurations are affected, or whether a user must open a message.","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000685,"input_tokens":4498,"output_tokens":471,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Check the Microsoft Security Response Center advisory for CVE-2026-123376 for affected builds, whether user interaction is needed, and the patch.","search":"'-123376':14A,17A '-2026':13A,16A 'affect':57B 'allow':68C 'attack':8A,46B,49B,52B,71C 'base':30B,61C 'buffer':4A,31B,62C 'code':10A,54B,74C 'cve':12A,15A 'execut':53B,73C 'heap':3A,29B,60C 'heap-bas':28B,59C 'let':6A,50B 'machin':58B 'microsoft':1A,18A,22B,34B,65C 'microsoft-offic':21B 'network':42B,77C 'offic':23B,35B,66C 'office':19A 'outlook':2A,20A,25B,36B,67C 'overflow':5A,32B,63C 'remot':11A 'run':9A 'success':48B 'trigger':39B 'unauthor':45B,70C 'window':26B","nicknames":[],"mitigations":[],"who_affected":"Machines running Microsoft Office Outlook. The sources do not say which Outlook builds or configurations are affected, or whether a user must open a message.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"everyone","plain_action":"Update Microsoft Outlook to the latest version through Microsoft Update once Microsoft releases a fix.","pkeys":["microsoftofficeoutlook","officeoutlook"],"ptokens":["microsoft","office","outlook"],"labels":["high","microsoftoffice","other","outlook","vendor","windows"],"campaign_type":null,"search_a":"'-123376':14A,17A '-2026':13A,16A 'attack':8A 'buffer':4A 'code':10A 'cve':12A,15A 'heap':3A 'let':6A 'microsoft':1A,18A 'office':19A 'outlook':2A,20A 'overflow':5A 'remot':11A 'run':9A","search_b":"'affect':57B 'attack':46B,49B,52B 'base':30B 'buffer':31B 'code':54B 'execut':53B 'heap':29B 'heap-bas':28B 'let':50B 'machin':58B 'microsoft':22B,34B 'microsoft-offic':21B 'network':42B 'offic':23B,35B 'outlook':25B,36B 'overflow':32B 'success':48B 'trigger':39B 'unauthor':45B 'window':26B","search_c":"'allow':68C 'attack':71C 'base':61C 'buffer':62C 'code':74C 'execut':73C 'heap':60C 'heap-bas':59C 'microsoft':65C 'network':77C 'offic':66C 'outlook':67C 'overflow':63C 'unauthor':70C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:20:40+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-2026-123376","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123376","severity":null,"published_at":"2026-11-10T19:20:40+00:00","modified_at":"2026-11-10T19:20:40+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"}