{"id":"CVE-2018-8639","kind":"vulnerability","aliases":["CVE-2018-8639"],"related":[],"title":"An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects…","description":"An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory, aka \"Win32k Elevation of Privilege Vulnerability.\" This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2019, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-8641.","summary":"A flaw in the Windows Win32k kernel component lets a logged-in local user release resources improperly and gain privilege escalation. A successful attacker can run arbitrary code in kernel mode, and the sources report it is exploited in the wild, including by ransomware operators.","severity":"high","cvss":8.4,"epss":null,"exploited":true,"exploited_at":"2025-03-03T00:00:00+00:00","products":[{"name":"Microsoft Windows","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1507","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1607","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1703","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1709","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1803","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1809","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 7","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 8.1","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows rt 8.1","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows server 2008","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows server 2008","fixed":[],"affected":"= r2","ecosystem":"vendor"},{"name":"microsoft windows server 2012","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows server 2012","fixed":[],"affected":"= r2","ecosystem":"vendor"},{"name":"microsoft windows server 2016","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows server 2019","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","infrastructure","multi-user-systems","ransomware","windows","windows-servers"],"not_affected_if":["no-local-user-access"],"how_to_check":null,"fix":"Apply the Microsoft mitigation for CVE-2018-8639 for your Windows version, per CISA's required action; the specific patch KB is not stated in the sources.\nIf no mitigation is available, discontinue use of the affected product.","status":"open","published_at":"2018-12-12T00:29:01+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:52:18+00:00","updated_at":"2026-10-23T22:29:05+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-10-23T20:52:18Z","model":"claude-haiku-5-5","output":{"fix":"Apply the Microsoft mitigation for CVE-2018-8639 for your Windows version, per CISA's required action; the specific patch KB is not stated in the sources.\nIf no mitigation is available, discontinue use of the affected product.","reach":"local","impact":"high","summary":"A flaw in the Windows Win32k kernel component lets a logged-in local user release resources improperly and gain privilege escalation. A successful attacker can run arbitrary code in kernel mode, and the sources report it is exploited in the wild, including by ransomware operators.","category":"infrastructure","who_cares":["windows","windows-servers","multi-user-systems"],"confidence":0.7,"needs_auth":"yes","worst_case":"local user gains kernel-mode code execution and full system control","analyst_note":"Find the Microsoft security update guide entry for CVE-2018-8639 to get affected Windows builds and the exact KB patch and check method.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["no-local-user-access"],"user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000465,"input_tokens":2686,"output_tokens":393,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2018':19A,22A,207C '-8639':20A,23A '-8641':208C '10':28A,32A,36A,40A,44A,48A,196C,198C '1507':29A '1607':33A '1703':37A '1709':41A '1803':45A '1809':49A '2008':63A,67A,179C,193C '2012':71A,75A,172C,185C '2016':79A,190C '2019':83A,182C '7':52A,169C '8.1':55A,59A,176C,187C 'affect':167C 'aka':160C 'arbitrari':122B 'attack':119B 'code':123B 'compon':12A,102B,152C 'cve':18A,21A,201C,206C 'elev':2A,142C,162C 'escal':116B 'exist':6A,146C 'exploit':84B,133B 'fail':13A,153C 'flaw':96B 'gain':114B 'handl':16A,156C 'id':202C 'improp':112B 'includ':137B 'infrastructur':85B 'kernel':101B,125B 'let':103B 'local':108B 'log':106B 'logged-in':105B 'memori':159C 'microsoft':24A,26A,30A,34A,38A,42A,46A,50A,53A,56A,60A,64A,68A,72A,76A,80A 'mode':126B 'multi':87B 'multi-user-system':86B 'object':17A,157C 'oper':140B 'privileg':4A,115B,144C,164C 'proper':15A,155C 'r2':173C,194C 'ransomwar':90B,139B 'releas':110B 'report':130B 'resourc':111B 'rt':58A,175C 'run':121B 'server':62A,66A,70A,74A,78A,82A,94B,171C,178C,181C,184C,189C,192C,199C 'sourc':129B 'success':118B 'system':89B 'uniqu':204C 'user':88B,109B 'vulner':5A,145C,165C 'wild':136B 'win32k':11A,100B,151C,161C 'window':8A,91B,93B,99B,148C,168C,170C,174C,177C,180C,183C,186C,188C,191C,195C,197C 'windows':25A,27A,31A,35A,39A,43A,47A,51A,54A,57A,61A,65A,69A,73A,77A,81A 'windows-serv':92B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2018-12-12T00:29:01+00:00","kev":{"dateAdded":"2025-03-03","dueDate":"2025-03-24","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":"Known"},"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2018-8639","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2018-8639","severity":null,"published_at":"2025-03-03T00:00:00+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-2018-8639","url":"https://nvd.nist.gov/vuln/detail/CVE-2018-8639","severity":null,"published_at":"2018-12-12T00:29:01+00:00","modified_at":"2026-06-17T02:05:14+00:00","first_seen_at":"2026-10-23T22:29:05+00:00","fetched_at":"2026-10-23T22:29:05+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"}