{"id":"CVE-2021-34448","kind":"vulnerability","aliases":["CVE-2021-34448"],"related":[],"title":"Microsoft Windows: Microsoft Windows Scripting Engine Memory Corruption Vulnerability","description":"Microsoft Windows Scripting Engine contains an unspecified vulnerability that allows for memory corruption.\n\nCISA required action: Apply updates per vendor instructions.","summary":"Microsoft Windows Scripting Engine has a memory corruption flaw that CISA lists as actively exploited. An attacker who can get the affected engine to process crafted content can corrupt memory and may run code on the machine.","severity":"critical","cvss":9.3,"epss":0.40062,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Microsoft Windows","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","infrastructure","windows"],"not_affected_if":[],"how_to_check":null,"fix":"Apply the Microsoft Windows updates for CVE-2021-34448 per vendor instructions, as CISA requires.","status":"open","published_at":"2021-07-16T21:15:09+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:41:25+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-10-23T21:41:25Z","model":"claude-haiku-5-5","output":{"fix":"Apply the Microsoft Windows updates for CVE-2021-34448 per vendor instructions, as CISA requires.\nunknown","reach":"unknown","impact":"high","summary":"Microsoft Windows Scripting Engine has a memory corruption flaw that CISA lists as actively exploited. An attacker who can get the affected engine to process crafted content can corrupt memory and may run code on the machine.","category":"infrastructure","who_cares":["windows"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Attacker may run code on the Windows machine via memory corruption.","analyst_note":"Find the Microsoft security update guide entry for CVE-2021-34448 to name the patched builds and the exact attack vector and user interaction.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":[],"user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.00045,"input_tokens":2821,"output_tokens":336,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Find the Microsoft security update guide entry for CVE-2021-34448 to name the patched builds and the exact attack vector and user interaction.","search":"'-2021':11A,14A '-34448':12A,15A 'action':73C 'activ':34B 'affect':42B 'allow':67C 'appli':74C 'attack':37B 'cisa':31B,71C 'code':54B 'contain':62C 'content':47B 'corrupt':8A,28B,49B,70C 'craft':46B 'cve':10A,13A 'engin':6A,24B,43B,61C 'exploit':18B,35B 'flaw':29B 'get':40B 'infrastructur':19B 'instruct':78C 'list':32B 'machin':57B 'may':52B 'memori':7A,27B,50B,69C 'microsoft':1A,3A,16A,21B,58C 'per':76C 'process':45B 'requir':72C 'run':53B 'script':5A,23B,60C 'unspecifi':64C 'updat':75C 'vendor':77C 'vulner':9A,65C 'window':2A,4A,20B,22B,59C 'windows':17A","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-07-16T21:15:09+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-34448","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-34448","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T17:39:59+00:00","note":null},{"source":"epss","external_id":"CVE-2021-34448","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-34448","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:43+00:00","fetched_at":"2026-10-23T19:13:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-34448","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-34448","severity":null,"published_at":"2021-07-16T21:15:09+00:00","modified_at":"2026-08-10T19:58:48+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","fetched_at":"2026-10-23T21:57:34+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"}