{"id":"CVE-2021-30661","published":"2021-09-08T15:15:13Z","modified":"2026-06-17T03:50:38Z","title":"Apple Multiple Products WebKit Storage Use-After-Free Vulnerability","vendor":"Apple","product":"Multiple Products","tier":"core","eol":null,"description":{"text":"A use after free issue was addressed with improved memory management. This issue is fixed in Safari 14.1, iOS 12.5.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5, macOS Big Sur 11.3. 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":"A use-after-free flaw in the WebKit component of Apple's multiple products, including Safari, iOS, iPadOS, watchOS, tvOS and macOS, lets malicious web content trigger memory corruption. An attacker can achieve arbitrary code execution over the network without authentication, but the victim must be induced to process the crafted web content, such as by visiting a malicious page.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:13:34Z"},"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":0.04491,"percentile":0.91461,"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-2021-30661","provenance":"source"},"vulncheckKev":{"dateAdded":"2021-04-26","exploitedFirstSeen":"2021-04-26","ransomware":false,"evidence":[{"url":"https://docs.google.com/spreadsheets/d/1lkNJ0uQwbeC1ZTRrxdtuPLCIl7mlUreoKfSIgajnSyY/edit","date":"2021-04-26"},{"url":"https://support.apple.com/kb/HT212317","date":"2021-04-26"},{"url":"https://support.apple.com/kb/HT212318","date":"2021-04-26"},{"url":"https://support.apple.com/kb/HT212323","date":"2021-04-26"},{"url":"https://support.apple.com/kb/HT212324","date":"2021-04-26"},{"url":"https://support.apple.com/kb/HT212325","date":"2021-04-26"},{"url":"https://support.apple.com/kb/HT212341","date":"2021-05-03"},{"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-416","name":"Use After Free"}],"references":[{"url":"https://support.apple.com/en-us/HT212317","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212318","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212323","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212324","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212325","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212341","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212317","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212318","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212323","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212324","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212325","tags":["Vendor Advisory"]},{"url":"https://support.apple.com/en-us/HT212341","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30661","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 delivered to victim browser","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"Processing maliciously crafted web content may lead to arbitrary code execution","start":188,"end":267}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1059","name":"Command and Scripting Interpreter","tactics":["execution"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: arbitrary code execution is the direct impact","mappingType":"primary_impact","evidence":[{"from":"description","quote":"may lead to arbitrary code execution","start":231,"end":267}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-17578","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-17578","exploited":true,"exploitedSince":"2021-11-03","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1189"],"provenance":"ai"},{"stage":"primary","techniques":["T1059"],"provenance":"ai"}],"timeline":[{"date":"2021-04-26","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-2021-30661","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-2021-17578","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":56},"priority":{"score":62.5,"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 2012 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":18.29,"detail":"percentile 0.9146"},{"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-416"}}