{"id":"CVE-2021-27085","kind":"vulnerability","aliases":["CVE-2021-27085"],"related":[],"title":"Microsoft Internet Explorer: Microsoft Internet Explorer Remote Code Execution Vulnerability","description":"Microsoft Internet Explorer contains an unspecified vulnerability that allows for remote code execution.\n\nCISA required action: Apply updates per vendor instructions.","summary":"Microsoft Internet Explorer contains an unspecified flaw that lets an attacker run code remotely. CISA lists it as actively exploited in the wild.","severity":"high","cvss":8.8,"epss":0.05448,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Microsoft Internet Explorer","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","internet-explorer","other","windows"],"not_affected_if":["internet-explorer-removed"],"how_to_check":null,"fix":"Apply updates per vendor instructions, as CISA requires; the sources do not name the fixed version.","status":"open","published_at":"2021-03-11T16:15:18+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:37:22+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-10-23T21:37:22Z","model":"claude-haiku-5-5","output":{"fix":"Apply updates per vendor instructions, as CISA requires; the sources do not name the fixed version.","reach":"unknown","impact":"high","summary":"Microsoft Internet Explorer contains an unspecified flaw that lets an attacker run code remotely. CISA lists it as actively exploited in the wild.","category":"other","who_cares":["internet-explorer","windows"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Attacker runs code remotely on the affected Windows machine.","analyst_note":"Find the Microsoft security update guide entry for CVE-2021-27085 to get the fixed builds, attack vector and whether user interaction is needed.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["internet-explorer-removed"],"user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.00044,"input_tokens":2824,"output_tokens":316,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Find the Microsoft security update guide entry for CVE-2021-27085 to get the fixed builds, attack vector and whether user interaction is needed.","search":"'-2021':12A,15A '-27085':13A,16A 'action':64C 'activ':44B 'allow':57C 'appli':65C 'attack':36B 'cisa':40B,62C 'code':8A,38B,60C 'contain':29B,52C 'cve':11A,14A 'execut':9A,61C 'exploit':20B,45B 'explor':3A,6A,23B,28B,51C 'explorer':19A 'flaw':32B 'instruct':69C 'internet':2A,5A,18A,22B,27B,50C 'internet-explor':21B 'let':34B 'list':41B 'microsoft':1A,4A,17A,26B,49C 'per':67C 'remot':7A,39B,59C 'requir':63C 'run':37B 'unspecifi':31B,54C 'updat':66C 'vendor':68C 'vulner':10A,55C 'wild':48B 'window':25B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-03-11T16:15:18+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:L/PR:N/UI:R/S:C/C:L/I:H/A:L","cvss_by":"secure@microsoft.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-27085","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-27085","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":"2026-10-25T20:35:39+00:00","note":null},{"source":"epss","external_id":"CVE-2021-27085","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-27085","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-2021-27085","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-27085","severity":null,"published_at":"2021-03-11T16:15:18+00:00","modified_at":"2026-08-19T19:22:43+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"}