{"cve":{"cve_id":"CVE-2021-1871","is_kev":true,"kev_date_added":"2021-11-03","kev_vendor_project":"Apple","kev_product":"iOS, iPadOS, and macOS","kev_vulnerability_name":"Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability","kev_short_description":"Apple iOS, iPadOS, and macOS WebKit contain an unspecified logic vulnerability that allows a remote attacker to execute code. 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.","kev_required_action":"Apply updates per vendor instructions.","kev_due_date":"2021-11-17","kev_known_ransomware":false,"kev_notes":"https://nvd.nist.gov/vuln/detail/CVE-2021-1871","kev_cwes":["CWE-1173"],"epss_score":0.0712,"epss_percentile":0.93426,"epss_as_of":"2026-06-23","description":"A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..","published_at":"2021-04-02T18:06:58Z","last_modified_at":null,"cvss_v3_score":9.8,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_v3_severity":"CRITICAL","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":"active","ssvc_automatable":true,"ssvc_technical_impact":"total","cwes":null,"nvd_references":["https://support.apple.com/en-us/HT212147","https://support.apple.com/en-us/HT212146","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/","https://www.debian.org/security/2021/dsa-4923"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:31.350578Z","updated_at":"2026-06-28T23:14:51.008528Z"},"effective_severity":"CRITICAL","badges":["kev"],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"apple","vendor_name":"Apple","product_slug":"ios-and-ipados","product_name":"iOS and iPadOS","version_start":"unspecified","version_start_inclusive":true,"version_end":"14.4","version_end_inclusive":false,"cpe23_uri":"cve5:apple:ios-and-ipados:unspecified:14.4"},{"vendor_slug":"apple","vendor_name":"Apple","product_slug":"macos","product_name":"macOS","version_start":"unspecified","version_start_inclusive":true,"version_end":"11.2","version_end_inclusive":false,"cpe23_uri":"cve5:apple:macos:unspecified:11.2"}],"exploit_refs":[],"news":[],"references":[{"url":"https://support.apple.com/en-us/HT212147","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://support.apple.com/en-us/HT212146","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/","source_type":"MAILING_LIST","tags":["mailing-list"]},{"url":"https://www.debian.org/security/2021/dsa-4923","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2021-04-02T18:06:58Z","label":"CVE published","source":null},{"type":"cisa_reported","at":"2021-11-03T00:00:00Z","label":"Added to CISA KEV catalog","source":"kev"},{"type":"ssvc_changed","at":"2026-06-24T00:31:36.955378Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:36.955378Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-24T00:31:36.955378Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:36.955378Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:36.955378Z","label":"CVSS score revised","source":"vulnrichment"},{"type":"cvss_changed","at":"2026-06-24T00:31:36.955378Z","label":"CVSS score revised","source":"vulnrichment"}]}