{"id":"CVE-2023-21674","published":"2023-01-10T22:15:16Z","modified":"2026-06-17T05:33:36Z","title":"Microsoft Windows Advanced Local Procedure Call (ALPC) Privilege Escalation Vulnerability","vendor":"Microsoft","product":"Windows","tier":"core","eol":null,"description":{"text":"Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability","provenance":"source","from":"NVD"},"summary":{"text":"A use-after-free flaw in the Windows Advanced Local Procedure Call (ALPC) component of Microsoft Windows allows privilege escalation. An attacker needs local access and low-privileged user credentials, with no user interaction required, to exploit it.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:12:32Z"},"cvss":{"score":8.8,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.34206,"percentile":0.984,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2023-01-10","dueDate":"2023-01-31","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2023-21674;  https://nvd.nist.gov/vuln/detail/CVE-2023-21674","provenance":"source"},"vulncheckKev":{"dateAdded":"2023-01-10","exploitedFirstSeen":"2023-01-10","ransomware":false,"evidence":[{"url":"https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2023-Jan","date":"2023-01-10"},{"url":"https://docs.google.com/spreadsheets/d/1lkNJ0uQwbeC1ZTRrxdtuPLCIl7mlUreoKfSIgajnSyY/edit","date":"2023-01-10"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2023-01-10"},{"url":"https://decoded.avast.io/threatresearch/avast-q4-2022-threat-report/","date":"2023-02-09"},{"url":"https://ti.qianxin.com/uploads/2024/02/02/dcc93e586f9028c68e7ab34c3326ff31.pdf","date":"2024-02-02"},{"url":"https://www.verizon.com/business/resources/T600/reports/2024-dbir-data-breach-investigations-report.pdf","date":"2024-05-01"}],"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-416","name":"Use After Free"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21674","tags":["Patch","Vendor Advisory"]},{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21674","tags":["Patch","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21674","tags":["US Government Resource"]}],"techniques":[{"id":"T1078","name":"Valid Accounts","tactics":["initial-access","persistence","privilege-escalation","stealth"],"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":"This vulnerability is exploited by an authenticated adversary. It is identified as requiring local access via Microsoft; however, other reports have identified remote, authenticated adversaries can exploit this vulnerability. A successful exploitation would grant an attacker SYSTEM level privileges. \n\nThis vulnerability has been exploited in the wild; however, technical details of how this was leveraged in an attack has not been publicly shared. ","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":"This vulnerability is exploited by an authenticated adversary. It is identified as requiring local access via Microsoft; however, other reports have identified remote, authenticated adversaries can exploit this vulnerability. A successful exploitation would grant an attacker SYSTEM level privileges. \n\nThis vulnerability has been exploited in the wild; however, technical details of how this was leveraged in an attack has not been publicly shared. ","confidence":"high"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2023-25841","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-25841","exploited":true,"exploitedSince":"2023-01-10","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":0,"earliest":"2024-03-07","earliestUrl":"https://github.com/hd3s5aa/CVE-2023-21674","repos":[{"name":"hd3s5aa/CVE-2023-21674","url":"https://github.com/hd3s5aa/CVE-2023-21674","stars":42,"created":"2024-03-07"}]},"first":{"date":"2024-03-07","source":"PoC-in-GitHub","url":"https://github.com/hd3s5aa/CVE-2023-21674"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1078"],"provenance":"source"},{"stage":"primary","techniques":["T1068"],"provenance":"source"}],"timeline":[{"date":"2023-01-10","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-21674","provenance":"source"},{"date":"2023-01-10","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2023-Jan","provenance":"source"},{"date":"2023-01-10","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2023-01-10","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-25841","provenance":"source"},{"date":"2024-03-07","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/hd3s5aa/CVE-2023-21674","provenance":"source"}],"speed":{"daysToPublicExploit":422,"firstExploitFrom":"PoC-in-GitHub","daysToKev":0},"priority":{"score":68.8,"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 1388 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.68,"detail":"percentile 0.9840"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 PoC-in-GitHub repo"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":6.16,"detail":"base score 8.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]},"lineage":{"familyId":"fam-class-microsoft-windows-cwe-416"}}