{"id":"CVE-2021-30665","published":"2021-09-08T15:15:13Z","modified":"2026-06-17T03:50:39Z","title":"Apple Multiple Products WebKit Memory Corruption Vulnerability","vendor":"Apple","product":"Multiple Products","tier":"core","eol":null,"description":{"text":"A memory corruption issue was addressed with improved state management. This issue is fixed in watchOS 7.4.1, iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..","provenance":"source","from":"NVD"},"summary":{"text":"The flaw is a memory corruption (out-of-bounds write) issue in WebKit, which affects multiple Apple products. An attacker who can get a user to load maliciously crafted web content can achieve arbitrary code execution, requiring no authentication but user interaction, such as visiting the page.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:13:41Z"},"cvss":{"score":8.8,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.03706,"percentile":0.89718,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2021-30665","provenance":"source"},"vulncheckKev":{"dateAdded":"2021-05-03","exploitedFirstSeen":"2021-05-03","ransomware":false,"evidence":[{"url":"https://docs.google.com/spreadsheets/d/1lkNJ0uQwbeC1ZTRrxdtuPLCIl7mlUreoKfSIgajnSyY/edit","date":"2021-05-03"},{"url":"https://support.apple.com/kb/HT212335","date":"2021-05-03"},{"url":"https://support.apple.com/kb/HT212336","date":"2021-05-03"},{"url":"https://support.apple.com/kb/HT212339","date":"2021-05-03"},{"url":"https://support.apple.com/kb/HT212341","date":"2021-05-03"},{"url":"https://support.apple.com/kb/HT212340","date":"2021-05-04"},{"url":"https://support.apple.com/kb/HT212532","date":"2021-05-24"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2021-11-03"}],"evidenceTotal":8,"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-787","name":"Out-of-bounds Write"}],"references":[{"url":"https://support.apple.com/en-us/HT212335","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212336","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212339","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212341","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212532","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212335","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212336","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212339","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212341","tags":["Release Notes","Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212532","tags":["Release Notes","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30665","tags":["Third Party Advisory","US Government Resource"]}],"techniques":[{"id":"T1189","name":"Drive-by Compromise","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: malicious web content triggers exploitation","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"Processing maliciously crafted web content may lead to arbitrary code execution","start":185,"end":264}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1203","name":"Exploitation for Client Execution","tactics":["execution"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: code runs in the browser or app context","mappingType":"primary_impact","evidence":[{"from":"description","quote":"may lead to arbitrary code execution","start":228,"end":264}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-17582","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-17582","exploited":true,"exploitedSince":"2021-11-03","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1189"],"provenance":"ai"},{"stage":"primary","techniques":["T1203"],"provenance":"ai"}],"timeline":[{"date":"2021-05-03","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://docs.google.com/spreadsheets/d/1lkNJ0uQwbeC1ZTRrxdtuPLCIl7mlUreoKfSIgajnSyY/edit","provenance":"source"},{"date":"2021-09-08","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-30665","provenance":"source"},{"date":"2021-11-03","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2021-11-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-17582","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":56},"priority":{"score":62.1,"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 2005 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":17.94,"detail":"percentile 0.8972"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"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-apple-ios-macos-cwe-787"}}