{"id":"CVE-2026-112971","kind":"vulnerability","aliases":["CVE-2026-112971"],"related":[],"title":"Windows SMB Client: heap overflow lets a local user gain higher privileges","description":"Heap-based buffer overflow in Windows SMB Client allows an authorized attacker to elevate privileges locally.","summary":"A heap-based buffer overflow in the Windows SMB Client lets an authorized local user elevate their privileges. An attacker who already has a foothold on the machine can gain higher rights than they were granted.","severity":"high","cvss":7.0,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"Windows SMB Client","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["infrastructure","smb","windows"],"not_affected_if":["no-local-users"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T19:18:47+00:00","first_seen_at":"2026-11-10T19:24:35+00:00","triaged_at":"2026-11-10T19:53:30+00:00","updated_at":"2026-11-10T19:53:30+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T19:53:30Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Windows SMB Client: heap overflow lets a local user gain higher privileges","impact":"high","summary":"A heap-based buffer overflow in the Windows SMB Client lets an authorized local user elevate their privileges. An attacker who already has a foothold on the machine can gain higher rights than they were granted.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["windows","smb"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"local user gains elevated system privileges on the machine","analyst_note":"Confirm affected Windows builds, the patch version and the Microsoft advisory for CVE-2026-112971; the sources give only the NVD description.","how_to_check":"- unknown","plain_action":"","product_name":"Windows SMB Client","needs_analyst":true,"not_affected_if":["no-local-users"],"who_is_affected":"Windows machines that use the SMB Client component are the affected systems. The attacker must already be an authorized user on the machine, so a remote attacker without local access cannot use this on its own. unknown whether specific Windows builds or configurations are excluded.","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000682,"input_tokens":4492,"output_tokens":465,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Confirm affected Windows builds, the patch version and the Microsoft advisory for CVE-2026-112971; the sources give only the NVD description.","search":"'-112971':15A,18A '-2026':14A,17A 'allow':71C 'alreadi':47B 'attack':45B,74C 'author':38B,73C 'base':28B,64C 'buffer':29B,65C 'client':3A,21A,35B,70C 'cve':13A,16A 'elev':41B,76C 'foothold':50B 'gain':10A,55B 'grant':61B 'heap':4A,27B,63C 'heap-bas':26B,62C 'higher':11A,56B 'infrastructur':22B 'let':6A,36B 'local':8A,39B,78C 'machin':53B 'overflow':5A,30B,66C 'privileg':12A,43B,77C 'right':57B 'smb':2A,20A,23B,34B,69C 'user':9A,40B 'window':1A,24B,33B,68C 'windows':19A","nicknames":[],"mitigations":[],"who_affected":"Windows machines that use the SMB Client component are the affected systems. The attacker must already be an authorized user on the machine, so a remote attacker without local access cannot use this on its own. unknown whether specific Windows builds or configurations are excluded.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":["smbclient","windowssmbclient"],"ptokens":["client","smb","windows"],"labels":["high","infrastructure","smb","vendor","windows"],"campaign_type":null,"search_a":"'-112971':15A,18A '-2026':14A,17A 'client':3A,21A 'cve':13A,16A 'gain':10A 'heap':4A 'higher':11A 'let':6A 'local':8A 'overflow':5A 'privileg':12A 'smb':2A,20A 'user':9A 'window':1A 'windows':19A","search_b":"'alreadi':47B 'attack':45B 'author':38B 'base':28B 'buffer':29B 'client':35B 'elev':41B 'foothold':50B 'gain':55B 'grant':61B 'heap':27B 'heap-bas':26B 'higher':56B 'infrastructur':22B 'let':36B 'local':39B 'machin':53B 'overflow':30B 'privileg':43B 'right':57B 'smb':23B,34B 'user':40B 'window':24B,33B","search_c":"'allow':71C 'attack':74C 'author':73C 'base':64C 'buffer':65C 'client':70C 'elev':76C 'heap':63C 'heap-bas':62C 'local':78C 'overflow':66C 'privileg':77C 'smb':69C 'window':68C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:18:47+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-112971","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-112971","severity":null,"published_at":"2026-11-10T19:18:47+00:00","modified_at":"2026-11-10T19:18:47+00:00","first_seen_at":"2026-11-10T19:24:35+00:00","fetched_at":"2026-11-10T19:24:35+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"}