{"id":"CVE-2026-21519","kind":"vulnerability","aliases":["CVE-2026-21519"],"related":[],"title":"Access of resource using incompatible type ('type confusion') in Desktop Window Manager allows an authorized…","description":"Microsoft Desktop Windows Manager contains a type confusion vulnerability that could allow an authorized attacker to elevate privileges locally.\n\nCISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","summary":"A type confusion bug in Microsoft Desktop Window Manager lets an already-authorized local user raise their privileges on Windows. CISA lists it as actively exploited in the wild.","severity":"high","cvss":7.8,"epss":null,"exploited":true,"exploited_at":"2026-02-10T00:00:00+00:00","products":[{"name":"Microsoft Windows","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1607","fixed":["10.0.14393.8868"],"affected":"< 10.0.14393.8868","ecosystem":"vendor"},{"name":"microsoft windows 10 1809","fixed":["10.0.17763.8389"],"affected":"< 10.0.17763.8389","ecosystem":"vendor"},{"name":"microsoft windows 10 21h2","fixed":["10.0.19044.6937"],"affected":"< 10.0.19044.6937","ecosystem":"vendor"},{"name":"microsoft windows 10 22h2","fixed":["10.0.19045.6937"],"affected":"< 10.0.19045.6937","ecosystem":"vendor"},{"name":"microsoft windows 11 23h2","fixed":["10.0.22631.6649"],"affected":"< 10.0.22631.6649","ecosystem":"vendor"},{"name":"microsoft windows 11 24h2","fixed":["10.0.26100.7781"],"affected":"< 10.0.26100.7781","ecosystem":"vendor"},{"name":"microsoft windows 11 25h2","fixed":["10.0.26200.7781"],"affected":"< 10.0.26200.7781","ecosystem":"vendor"},{"name":"microsoft windows server 2016","fixed":["10.0.14393.8868"],"affected":"< 10.0.14393.8868","ecosystem":"vendor"},{"name":"microsoft windows server 2019","fixed":["10.0.17763.8389"],"affected":"< 10.0.17763.8389","ecosystem":"vendor"},{"name":"microsoft windows server 2022","fixed":["10.0.20348.4711"],"affected":"< 10.0.20348.4711","ecosystem":"vendor"},{"name":"microsoft windows server 2022 23h2","fixed":["10.0.25398.2149"],"affected":"< 10.0.25398.2149","ecosystem":"vendor"},{"name":"microsoft windows server 2025","fixed":["10.0.26100.32313"],"affected":"< 10.0.26100.32313","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["desktop","exploited","infrastructure","multi-user-hosts","windows"],"not_affected_if":["no-local-user-access"],"how_to_check":null,"fix":"Apply the Microsoft mitigation or security update for CVE-2026-21519 per vendor instructions; the sources do not name the patched build.\nIf no mitigation is available, CISA says to discontinue use of the affected product.","status":"open","published_at":"2026-02-10T00:00:00+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:42:21+00:00","updated_at":"2026-10-23T23:44:51+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-23T20:42:21Z","model":"claude-haiku-5-5","output":{"fix":"Apply the Microsoft mitigation or security update for CVE-2026-21519 per vendor instructions; the sources do not name the patched build.\nIf no mitigation is available, CISA says to discontinue use of the affected product.","reach":"local","summary":"A type confusion bug in Microsoft Desktop Window Manager lets an already-authorized local user raise their privileges on Windows. CISA lists it as actively exploited in the wild.","category":"infrastructure","who_cares":["windows","desktop","multi-user-hosts"],"confidence":0.6,"needs_auth":"yes","worst_case":"A local low-privilege user gains elevated privileges on the Windows machine, possibly full system control.","analyst_note":"Find the Microsoft MSRC advisory for CVE-2026-21519 to get affected builds, patched KB numbers and any mitigation steps; sources here do not give them.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["no-local-user-access"],"user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000444,"input_tokens":2523,"output_tokens":384,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-01':142C '-2026':17A,20A '-21519':18A,21A '10':26A,30A,34A,38A '11':42A,46A,50A '1607':27A '1809':31A '2016':55A '2019':59A '2022':63A,67A '2025':72A '21h2':35A '22':141C '22h2':39A '23h2':43A,68A '24h2':47A '25h2':51A 'access':1A 'action':132C 'activ':106B 'allow':13A,122C 'alreadi':93B 'already-author':92B 'appli':133C 'applic':139C 'attack':125C 'author':15A,94B,124C 'bod':140C 'bug':84B 'cisa':102B,130C 'cloud':145C 'confus':8A,83B,118C 'contain':115C 'could':121C 'cve':16A,19A 'desktop':10A,73B,87B,112C 'discontinu':148C 'elev':127C 'exploit':74B,107B 'follow':138C 'guidanc':143C 'host':79B 'incompat':5A 'infrastructur':75B 'instruct':137C 'let':90B 'list':103B 'local':95B,129C 'manag':12A,89B,114C 'microsoft':22A,24A,28A,32A,36A,40A,44A,48A,52A,56A,60A,64A,69A,86B,111C 'mitig':134C,154C 'multi':77B 'multi-user-host':76B 'per':135C 'privileg':99B,128C 'product':152C 'rais':97B 'requir':131C 'resourc':3A 'server':54A,58A,62A,66A,71A 'servic':146C 'type':6A,7A,82B,117C 'unavail':156C 'use':4A,149C 'user':78B,96B 'vendor':136C 'vulner':119C 'wild':110B 'window':11A,80B,88B,101B,113C 'windows':23A,25A,29A,33A,37A,41A,45A,49A,53A,57A,61A,65A,70A","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2026-02-10T00:00:00+00:00","kev":{"dateAdded":"2026-02-10","dueDate":"2026-03-03","requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","knownRansomwareCampaignUse":"Unknown"},"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":"kev","external_id":"CVE-2026-21519","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-21519","severity":null,"published_at":"2026-02-10T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T13:39:29+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-21519","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21519","severity":null,"published_at":"2026-02-10T18:16:34+00:00","modified_at":"2026-06-17T10:18:46+00:00","first_seen_at":"2026-10-23T23:44:51+00:00","fetched_at":"2026-10-23T23:44:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}