{"id":"CVE-2018-8639","published":"2018-12-12T00:29:01Z","modified":"2026-06-17T02:05:14Z","title":"Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability","vendor":"Microsoft","product":"Windows","tier":"core","eol":null,"description":{"text":"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.","provenance":"source","from":"NVD"},"summary":{"text":"Microsoft Windows contains a privilege escalation flaw in the Win32k component, which fails to properly handle objects in memory. An attacker with local access and low-privileged credentials, requiring no user interaction, could exploit this to elevate their privileges on the system.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:05:27Z"},"cvss":{"score":7.8,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.22179,"percentile":0.97664,"date":"2026-10-28","provenance":"source"},"kev":{"dateAdded":"2025-03-03","dueDate":"2025-03-24","ransomware":true,"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.","notes":"https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2018-8639 ; https://nvd.nist.gov/vuln/detail/CVE-2018-8639","provenance":"source"},"vulncheckKev":{"dateAdded":"2020-06-24","exploitedFirstSeen":"2020-06-24","ransomware":true,"evidence":[{"url":"https://securelist.com/magnitude-exploit-kit-evolution/97436/","date":"2020-06-24"},{"url":"https://www.ic3.gov/Media/News/2022/220126.pdf","date":"2022-01-26"},{"url":"https://asec.ahnlab.com/en/47455/","date":"2023-02-13"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2025-03-03"},{"url":"https://www.acronis.com/en/tru/posts/makop-ransomware-guloader-and-privilege-escalation-in-attacks-against-indian-businesses/","date":"2025-12-08"},{"url":"https://www.loginsoft.com/reports/annually/vulnerability-intelligence-report-2025","date":"2026-01-20"}],"evidenceTotal":6,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-404","name":"Improper Resource Shutdown or Release"}],"references":[{"url":"http://www.securityfocus.com/bid/106093","tags":["Broken Link","Third Party Advisory","VDB Entry"]},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639","tags":["Patch","Vendor Advisory"]},{"url":"http://www.securityfocus.com/bid/106093","tags":["Broken Link","Third Party Advisory","VDB Entry"]},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639","tags":["Patch","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8639","tags":["US Government Resource"]}],"techniques":[{"id":"T1068","name":"Exploitation for Privilege Escalation","tactics":["privilege-escalation"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Local privilege escalation via Win32k memory handling flaw","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory","start":0,"end":126}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2018-20250","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2018-20250","exploited":true,"exploitedSince":"2025-03-03","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":2,"skipped":0,"earliest":"2019-03-05","earliestUrl":"https://github.com/ze0r/CVE-2018-8639-exp","repos":[{"name":"ze0r/CVE-2018-8639-exp","url":"https://github.com/ze0r/CVE-2018-8639-exp","stars":125,"created":"2019-03-05"},{"name":"timwhitez/CVE-2018-8639-EXP","url":"https://github.com/timwhitez/CVE-2018-8639-EXP","stars":5,"created":"2019-12-27"}]},"first":{"date":"2019-03-05","source":"PoC-in-GitHub","url":"https://github.com/ze0r/CVE-2018-8639-exp"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1068"],"provenance":"ai"}],"timeline":[{"date":"2018-12-12","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2018-8639","provenance":"source"},{"date":"2019-03-05","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/ze0r/CVE-2018-8639-exp","provenance":"source"},{"date":"2020-06-24","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://securelist.com/magnitude-exploit-kit-evolution/97436/","provenance":"source"},{"date":"2025-03-03","kind":"kev","label":"Added to CISA KEV (known ransomware use)","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2025-03-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2018-20250","provenance":"source"}],"speed":{"daysToPublicExploit":83,"firstExploitFrom":"PoC-in-GitHub","daysToKev":2273},"priority":{"score":78.0,"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 2318 days ago"},{"name":"Known ransomware use","points":10.0,"detail":"CISA KEV and VulnCheck KEV: Known"},{"name":"EPSS percentile","points":19.53,"detail":"percentile 0.9766"},{"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":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":5.46,"detail":"base score 7.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}