{"id":"CVE-2026-118221","kind":"vulnerability","aliases":["CVE-2026-118221"],"related":[],"title":"Windows: heap buffer overflow lets a local user gain higher privileges","description":"Heap-based buffer overflow in Windows Advanced Rasterization Platform allows an authorized attacker to elevate privileges locally.","summary":"A heap-based buffer overflow in the Windows Advanced Rasterization Platform lets an already-authorized local user overwrite memory. An attacker who can run code on the machine can use it to elevate privileges.","severity":"high","cvss":8.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","windows"],"not_affected_if":["no-local-users"],"how_to_check":"Run winver and compare the build against the MSRC Update Guide entry for CVE-2026-118221 (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118221); run Get-HotFix or Settings > Windows Update to confirm the latest cumulative update is installed. Affected builds and the patched KB are not yet confirmed here.","fix":null,"status":"open","published_at":"2026-11-10T19:19:39+00:00","first_seen_at":"2026-11-10T19:24:50+00:00","triaged_at":"2026-11-10T19:30:08+00:00","updated_at":"2026-11-10T23:19:17+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T19:30:08Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Windows: heap buffer overflow lets a local user gain higher privileges","impact":"high","summary":"A heap-based buffer overflow in the Windows Advanced Rasterization Platform lets an already-authorized local user overwrite memory. An attacker who can run code on the machine can use it to elevate privileges.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["windows"],"confidence":0.6,"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-2026-118221 to get affected builds and the patched cumulative update.","how_to_check":"- Check the installed Windows build with `winver` and compare it against the Microsoft security update that lists CVE-2026-118221.\n- Confirm Windows Update is enabled and has installed the latest cumulative updates.","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-local-users"],"who_is_affected":"Affects Windows systems where a user already has a local account and can run code. The sources do not list affected Windows builds or the patched version. Systems with no untrusted local users carry lower practical risk.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.00069,"input_tokens":4502,"output_tokens":480,"severity_before":"high"},"analyst_status":"done","analyst_note":"Find the Microsoft security update guide entry for CVE-2026-118221 to get affected builds and the patched cumulative update.","search":"'-118221':14A,17A '-2026':13A,16A 'advanc':29B,63C 'allow':66C 'alreadi':35B 'already-author':34B 'attack':42B,69C 'author':36B,68C 'base':23B,58C 'buffer':3A,24B,59C 'code':46B 'cve':12A,15A 'elev':54B,71C 'gain':9A 'heap':2A,22B,57C 'heap-bas':21B,56C 'higher':10A 'infrastructur':18B 'let':5A,32B 'local':7A,37B,73C 'machin':49B 'memori':40B 'overflow':4A,25B,60C 'overwrit':39B 'platform':31B,65C 'privileg':11A,55B,72C 'raster':30B,64C 'run':45B 'use':51B 'user':8A,38B 'window':1A,19B,28B,62C","nicknames":[],"mitigations":[],"who_affected":"Affects Windows systems where a user already has a local account and can run code. The sources do not list affected Windows builds or the patched version. Systems with no untrusted local users carry lower practical risk.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","infrastructure","windows"],"campaign_type":null,"search_a":"'-118221':14A,17A '-2026':13A,16A 'buffer':3A 'cve':12A,15A 'gain':9A 'heap':2A 'higher':10A 'let':5A 'local':7A 'overflow':4A 'privileg':11A 'user':8A 'window':1A","search_b":"'advanc':29B 'alreadi':35B 'already-author':34B 'attack':42B 'author':36B 'base':23B 'buffer':24B 'code':46B 'elev':54B 'heap':22B 'heap-bas':21B 'infrastructur':18B 'let':32B 'local':37B 'machin':49B 'memori':40B 'overflow':25B 'overwrit':39B 'platform':31B 'privileg':55B 'raster':30B 'run':45B 'use':51B 'user':38B 'window':19B,28B","search_c":"'advanc':63C 'allow':66C 'attack':69C 'author':68C 'base':58C 'buffer':59C 'elev':71C 'heap':57C 'heap-bas':56C 'local':73C 'overflow':60C 'platform':65C 'privileg':72C 'raster':64C 'window':62C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T19:19:39+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-118221","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118221","severity":null,"published_at":"2026-11-10T19:19:39+00:00","modified_at":"2026-11-10T19:19:39+00:00","first_seen_at":"2026-11-10T19:24:50+00:00","fetched_at":"2026-11-10T19:24:50+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-118221:3144","url":null,"severity":null,"published_at":"2026-11-10T23:19:17+00:00","modified_at":"2026-11-10T23:19:17+00:00","first_seen_at":"2026-11-10T23:19:17+00:00","fetched_at":"2026-11-10T23:19:17+00:00","note":"MSRC update guide and CVRF API returned no readable content (JS-only); only NVD/Rapid7 mirror the CVE text. No affected builds, KB or patched CVE-2026-118221 version confirmed; nothing verified. Revisit when MSRC page is readable (Nov 2026 Patch Tuesday cumulative updates likely carry the fix, unconfirmed). No exploitation or PoC seen."}],"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"}