{"id":"CVE-2026-83563","kind":"vulnerability","aliases":["CVE-2026-83563"],"related":[],"title":"Windows Winlogon: heap overflow lets a local user gain higher privileges","description":"Heap-based buffer overflow in Winlogon allows an authorized attacker to elevate privileges locally.","summary":"A heap-based buffer overflow in Windows Winlogon, the logon component, lets an authorized local user elevate their privileges. The sources do not give affected versions, fixed builds, or a patch reference.","severity":"high","cvss":7.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","windows","winlogon"],"not_affected_if":["no-local-accounts"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T19:21:23+00:00","first_seen_at":"2026-11-10T19:25:17+00:00","triaged_at":"2026-11-10T19:38:47+00:00","updated_at":"2026-11-10T19:38:47+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T19:38:47Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Windows Winlogon: heap overflow lets a local user gain higher privileges","impact":"high","summary":"A heap-based buffer overflow in Windows Winlogon, the logon component, lets an authorized local user elevate their privileges. The sources do not give affected versions, fixed builds, or a patch reference.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["windows","winlogon"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"local user gains SYSTEM-level privileges on the machine","analyst_note":"Find the Microsoft security update guide entry for CVE-2026-83563 to confirm affected Windows builds, fixed versions and patch names.","how_to_check":"unknown","plain_action":"","product_name":"Windows Winlogon","needs_analyst":true,"not_affected_if":["no-local-accounts"],"who_is_affected":"Only users who already have a local account on the Windows machine can use this flaw to gain higher privileges. The sources do not name affected Windows builds, so check the vendor's security update notes for this CVE. unknown","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000678,"input_tokens":4486,"output_tokens":459,"severity_before":"high"},"analyst_status":"queued","analyst_note":"Find the Microsoft security update guide entry for CVE-2026-83563 to confirm affected Windows builds, fixed versions and patch names.","search":"'-2026':13A,16A '-83563':14A,17A 'affect':46B 'allow':61C 'attack':64C 'author':35B,63C 'base':24B,56C 'buffer':25B,57C 'build':49B 'compon':32B 'cve':12A,15A 'elev':38B,66C 'fix':48B 'gain':9A 'give':45B 'heap':3A,23B,55C 'heap-bas':22B,54C 'higher':10A 'infrastructur':18B 'let':5A,33B 'local':7A,36B,68C 'logon':31B 'overflow':4A,26B,58C 'patch':52B 'privileg':11A,40B,67C 'refer':53B 'sourc':42B 'user':8A,37B 'version':47B 'window':1A,19B,28B 'winlogon':2A,20B,29B,60C","nicknames":[],"mitigations":[],"who_affected":"Only users who already have a local account on the Windows machine can use this flaw to gain higher privileges. The sources do not name affected Windows builds, so check the vendor's security update notes for this CVE. unknown","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","infrastructure","windows","winlogon"],"campaign_type":null,"search_a":"'-2026':13A,16A '-83563':14A,17A 'cve':12A,15A 'gain':9A 'heap':3A 'higher':10A 'let':5A 'local':7A 'overflow':4A 'privileg':11A 'user':8A 'window':1A 'winlogon':2A","search_b":"'affect':46B 'author':35B 'base':24B 'buffer':25B 'build':49B 'compon':32B 'elev':38B 'fix':48B 'give':45B 'heap':23B 'heap-bas':22B 'infrastructur':18B 'let':33B 'local':36B 'logon':31B 'overflow':26B 'patch':52B 'privileg':40B 'refer':53B 'sourc':42B 'user':37B 'version':47B 'window':19B,28B 'winlogon':20B,29B","search_c":"'allow':61C 'attack':64C 'author':63C 'base':56C 'buffer':57C 'elev':66C 'heap':55C 'heap-bas':54C 'local':68C 'overflow':58C 'privileg':67C 'winlogon':60C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:21:23+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:L/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-2026-83563","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-83563","severity":null,"published_at":"2026-11-10T19:21:23+00:00","modified_at":"2026-11-10T19:21:23+00:00","first_seen_at":"2026-11-10T19:25:17+00:00","fetched_at":"2026-11-10T19:25:17+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"}