{"id":"CVE-2023-21674","kind":"vulnerability","aliases":["CVE-2023-21674"],"related":[],"title":"Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability","description":"Microsoft Windows Advanced Local Procedure Call (ALPC) contains an unspecified vulnerability that allows for privilege escalation.\n\nCISA required action: Apply updates per vendor instructions.","summary":"Microsoft Windows' Advanced Local Procedure Call (ALPC) component has an unspecified flaw that lets a local user escalate privileges. Exploitation is confirmed in the wild, per CISA's Known Exploited Vulnerabilities catalog.","severity":"high","cvss":8.8,"epss":null,"exploited":true,"exploited_at":"2023-01-10T00:00:00+00:00","products":[{"name":"Microsoft Windows","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows 10 1507","fixed":["10.0.10240.19685"],"affected":"< 10.0.10240.19685","ecosystem":"vendor"},{"name":"microsoft windows 10 1607","fixed":["10.0.14393.5648"],"affected":"< 10.0.14393.5648","ecosystem":"vendor"},{"name":"microsoft windows 10 1809","fixed":["10.0.17763.3887"],"affected":"< 10.0.17763.3887","ecosystem":"vendor"},{"name":"microsoft windows 10 20h2","fixed":["10.0.19042.2486"],"affected":"< 10.0.19042.2486","ecosystem":"vendor"},{"name":"microsoft windows 10 21h2","fixed":["10.0.19044.2486"],"affected":"< 10.0.19044.2486","ecosystem":"vendor"},{"name":"microsoft windows 10 22h2","fixed":["10.0.19045.2486"],"affected":"< 10.0.19045.2486","ecosystem":"vendor"},{"name":"microsoft windows 11 21h2","fixed":["10.0.22000.1455"],"affected":"< 10.0.22000.1455","ecosystem":"vendor"},{"name":"microsoft windows 11 22h2","fixed":["10.0.22621.1105"],"affected":"< 10.0.22621.1105","ecosystem":"vendor"},{"name":"microsoft windows rt 8.1","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"microsoft windows server 2012","fixed":[],"affected":"= r2","ecosystem":"vendor"},{"name":"microsoft windows server 2016","fixed":["10.0.14393.5648"],"affected":"< 10.0.14393.5648","ecosystem":"vendor"},{"name":"microsoft windows server 2019","fixed":["10.0.17763.3887"],"affected":"< 10.0.17763.3887","ecosystem":"vendor"},{"name":"microsoft windows server 2022","fixed":["10.0.20348.1487"],"affected":"< 10.0.20348.1487","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","infrastructure","windows"],"not_affected_if":["non-windows"],"how_to_check":null,"fix":"Apply the Microsoft Windows security update per vendor instructions (CISA required action); the specific KB or build is unknown from these sources.","status":"open","published_at":"2023-01-10T00:00:00+00:00","first_seen_at":"2026-10-23T19:11:52+00:00","triaged_at":"2026-10-23T21:08:48+00:00","updated_at":"2026-10-23T22:29:04+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-10-23T21:08:48Z","model":"claude-haiku-5-5","output":{"fix":"Apply the Microsoft Windows security update per vendor instructions (CISA required action); the specific KB or build is unknown from these sources.","reach":"local","impact":"high","summary":"Microsoft Windows' Advanced Local Procedure Call (ALPC) component has an unspecified flaw that lets a local user escalate privileges. Exploitation is confirmed in the wild, per CISA's Known Exploited Vulnerabilities catalog.","category":"infrastructure","who_cares":["windows"],"confidence":0.7,"needs_auth":"yes","worst_case":"Local attacker with low privileges gains SYSTEM-level control of the machine.","analyst_note":"Find the Microsoft security update guide entry for CVE-2023-21674 to get the patched Windows builds and KB numbers, and confirm the affected versions.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["non-windows"],"user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.00046,"input_tokens":2805,"output_tokens":358,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2023':12A,15A '-21674':13A,16A '10':21A,25A,29A,33A,37A,41A '11':45A,49A '1507':22A '1607':26A '1809':30A '2012':58A '2016':62A '2019':66A '2022':70A '20h2':34A '21h2':38A,46A '22h2':42A,50A '8.1':54A 'action':124C 'advanc':2A,76B,108C 'allow':118C 'alpc':6A,80B,112C 'appli':125C 'call':5A,79B,111C 'catalog':105B 'cisa':100B,122C 'compon':81B 'confirm':95B 'contain':113C 'cve':11A,14A 'elev':7A 'escal':91B,121C 'exploit':71B,93B,103B 'flaw':85B 'infrastructur':72B 'instruct':129C 'known':102B 'let':87B 'local':3A,77B,89B,109C 'microsoft':17A,19A,23A,27A,31A,35A,39A,43A,47A,51A,55A,59A,63A,67A,74B,106C 'per':99B,127C 'privileg':9A,92B,120C 'procedur':4A,78B,110C 'requir':123C 'rt':53A 'server':57A,61A,65A,69A 'unspecifi':84B,115C 'updat':126C 'user':90B 'vendor':128C 'vulner':10A,104B,116C 'wild':98B 'window':1A,73B,75B,107C 'windows':18A,20A,24A,28A,32A,36A,40A,44A,48A,52A,56A,60A,64A,68A","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2023-01-10T00:00:00+00:00","kev":{"dateAdded":"2023-01-10","dueDate":"2023-01-31","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2023-21674","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-21674","severity":null,"published_at":"2023-01-10T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:52+00:00","fetched_at":"2026-10-25T12:39:23+00:00","note":null},{"source":"nvd","external_id":"CVE-2023-21674","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-21674","severity":null,"published_at":"2023-01-10T22:15:16+00:00","modified_at":"2026-06-17T05:33:36+00:00","first_seen_at":"2026-10-23T22:29:04+00:00","fetched_at":"2026-10-23T22:29:04+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"}