{"id":"CVE-2021-33739","published":"2021-06-08T23:15:09Z","modified":"2026-06-17T03:55:08Z","title":"Microsoft Desktop Window Manager (DWM) Core Library Privilege Escalation Vulnerability","vendor":"Microsoft","product":"Windows","tier":"core","eol":null,"description":{"text":"Microsoft DWM Core Library Elevation of Privilege Vulnerability","provenance":"source","from":"NVD"},"summary":{"text":"The Microsoft Desktop Window Manager (DWM) Core Library in Microsoft Windows contains a privilege escalation flaw. An attacker with local access can exploit it without authentication or user interaction to gain elevated privileges, resulting in high impact to confidentiality, integrity and availability.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:13:32Z"},"cvss":{"score":8.4,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.06555,"percentile":0.93813,"date":"2026-10-31","provenance":"source"},"kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2021-33739","provenance":"source"},"vulncheckKev":{"dateAdded":"2021-06-08","exploitedFirstSeen":"2021-06-08","ransomware":false,"evidence":[{"url":"https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2021-Jun","date":"2021-06-08"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2021-11-03"}],"evidenceTotal":2,"provenance":"source"},"exploited":true,"otx":null,"cwes":[],"references":[{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33739","tags":["Patch","Vendor Advisory"]},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33739","tags":["Patch","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33739","tags":["US Government Resource"]}],"techniques":[{"id":"T1598.002","name":"Spearphishing Attachment","tactics":["reconnaissance"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Privilege Escalation","mappingType":"exploitation_technique","evidence":[],"comment":"Local escalation of privilege attack. Attacker would most likely gain access through an executable or script on the local computer sent to the user via an email attachment.","confidence":"high"},{"id":"T1068","name":"Exploitation for Privilege Escalation","tactics":["privilege-escalation"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Privilege Escalation","mappingType":"primary_impact","evidence":[],"comment":"Local escalation of privilege attack. Attacker would most likely gain access through an executable or script on the local computer sent to the user via an email attachment.","confidence":"high"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-20416","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-20416","exploited":true,"exploitedSince":"2021-11-03","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":2,"skipped":0,"earliest":"2021-06-09","earliestUrl":"https://github.com/freeide2017/CVE-2021-33739-POC","repos":[{"name":"freeide2017/CVE-2021-33739-POC","url":"https://github.com/freeide2017/CVE-2021-33739-POC","stars":10,"created":"2021-06-09"},{"name":"giwon9977/CVE-2021-33739_PoC_Analysis","url":"https://github.com/giwon9977/CVE-2021-33739_PoC_Analysis","stars":5,"created":"2021-09-24"}]},"first":{"date":"2021-06-09","source":"PoC-in-GitHub","url":"https://github.com/freeide2017/CVE-2021-33739-POC"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1598.002"],"provenance":"source"},{"stage":"primary","techniques":["T1068"],"provenance":"source"}],"timeline":[{"date":"2021-06-08","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-33739","provenance":"source"},{"date":"2021-06-08","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2021-Jun","provenance":"source"},{"date":"2021-06-09","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/freeide2017/CVE-2021-33739-POC","provenance":"source"},{"date":"2021-11-03","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2021-11-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-20416","provenance":"source"}],"speed":{"daysToPublicExploit":1,"firstExploitFrom":"PoC-in-GitHub","daysToKev":148},"priority":{"score":64.6,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 1972 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":18.76,"detail":"percentile 0.9381"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"2 PoC-in-GitHub repos"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":5.88,"detail":"base score 8.4"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}