{"id":"CVE-2021-40449","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-40449","generatedAt":"2026-10-31T14:08:25.709Z","title":"Microsoft Windows Win32k Privilege Escalation Vulnerability","description":"Win32k Elevation of Privilege Vulnerability","published":"2021-10-13T01:15:10.000Z","lastModified":"2026-06-17T04:06:56.000Z","status":"Analyzed","sourceIdentifier":"secure@microsoft.com","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-416"],"affected":["microsoft/windows 10 1507","microsoft/windows 10 1607","microsoft/windows 10 1809","microsoft/windows 10 1909","microsoft/windows 10 2004","microsoft/windows 10 20h2","microsoft/windows 10 21h1","microsoft/windows 11","microsoft/windows 11 21h2","microsoft/windows 7","microsoft/windows 8.1","microsoft/windows rt 8.1","microsoft/windows server 2004","microsoft/windows server 2008","microsoft/windows server 2012","microsoft/windows server 2016","microsoft/windows server 2019","microsoft/windows server 2022","microsoft/windows server 20h2"],"epss":{"score":0.81936,"percentile":0.9965,"date":"2026-10-30","history":[{"date":"2026-10-19","score":0.81936,"percentile":0.9965}]},"kev":{"listed":true,"dateAdded":"2021-11-17","dueDate":"2021-12-01","knownRansomwareCampaignUse":"Known","notes":"Apply updates per vendor instructions.\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-40449"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 1 December 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-10-19T00:00:00.000Z","detail":{"to":0.81936,"from":0.74129,"percentile":0.9965},"summary":"EPSS moved from 74.1% to 81.9% probability of exploitation in the next thirty days."}],"references":[{"url":"http://packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"secure@microsoft.com"},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40449","tags":["Patch","Vendor Advisory"],"source":"secure@microsoft.com"},{"url":"http://packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40449","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40449","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-40449","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}