{"id":"CVE-2021-30761","kind":"vulnerability","aliases":["CVE-2021-30761"],"related":[],"title":"Apple iOS: Apple iOS WebKit Memory Corruption Vulnerability","description":"Apple iOS WebKit contains a memory corruption vulnerability that leads to code execution when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.\n\nCISA required action: Apply updates per vendor instructions.","summary":"Apple iOS WebKit has a memory corruption bug that is triggered by processing maliciously crafted web content. An attacker who gets a victim to load a booby-trapped page can run code.","severity":"high","cvss":8.8,"epss":0.10545,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Apple iOS","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","ios","ipad","iphone","safari","vendor","webkit"],"not_affected_if":["up-to-date-ios"],"how_to_check":"Settings > General > About on the iPhone or iPad shows the iOS version; compare it with the fixed release listed by Apple.","fix":"Update iOS to the release Apple lists as fixing CVE-2021-30761 (CISA says: apply updates per vendor instructions).","status":"open","published_at":"2021-09-08T14:15:10+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:34:00+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"vendor","confidence":0.7,"triage":{"at":"2026-10-23T21:34:00Z","model":"claude-haiku-5-5","output":{"fix":"Update iOS to the release Apple lists as fixing CVE-2021-30761 (CISA says: apply updates per vendor instructions).\nunknown","reach":"internet","impact":"high","summary":"Apple iOS WebKit has a memory corruption bug that is triggered by processing maliciously crafted web content. An attacker who gets a victim to load a booby-trapped page can run code.","category":"vendor","who_cares":["ios","iphone","ipad","safari","webkit"],"confidence":0.7,"needs_auth":"no","worst_case":"Attacker runs code on the device after the victim opens a crafted web page","analyst_note":"Sources do not name the fixed iOS version; check Apple's security releases page for CVE-2021-30761 and confirm the fixed versions.","how_to_check":"Settings > General > About on the iPhone or iPad shows the iOS version; compare it with the fixed release listed by Apple.\nunknown","needs_analyst":true,"not_affected_if":["up-to-date-ios"],"user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000481,"input_tokens":2874,"output_tokens":388,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2021':10A,13A '-30761':11A,14A 'action':106C 'appl':1A,3A,24B,57C,90C,95C 'apple':15A 'appli':107C 'attack':42B 'boobi':51B 'booby-trap':50B 'bug':31B 'cisa':104C 'code':56B,68C 'contain':60C 'content':40B,75C 'corrupt':7A,30B,63C 'could':78C 'craft':38B,73C 'cve':9A,12A 'execut':69C 'exploit':17B 'get':44B 'html':80C,102C 'impact':79C 'includ':85C 'instruct':111C 'io':2A,4A,18B,25B,58C 'ios':16A 'ipad':19B 'iphon':20B 'lead':66C 'limit':88C 'load':48B 'malici':37B,72C 'memori':6A,29B,62C 'non':94C 'non-appl':93C 'page':53B 'parser':81C 'per':109C 'process':36B,71C,103C 'product':96C 'reli':98C 'requir':105C 'run':55B 'safari':21B,91C 'trap':52B 'trigger':34B 'updat':108C 'use':83C 'vendor':22B,110C 'victim':46B 'vulner':8A,64C,77C 'web':39B,74C 'webkit':5A,23B,26B,59C,84C,100C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-09-08T14:15:10+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:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-30761","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-30761","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":"2026-10-25T13:39:32+00:00","note":null},{"source":"epss","external_id":"CVE-2021-30761","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-30761","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:44+00:00","fetched_at":"2026-10-23T19:13:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-30761","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-30761","severity":null,"published_at":"2021-09-08T14:15:10+00:00","modified_at":"2026-06-17T03:50:50+00:00","first_seen_at":"2026-10-23T21:57:35+00:00","fetched_at":"2026-10-23T21:57:35+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"}