{"schema":"threatline.record/2","record":{"id":"CVE-2021-1879","aliases":[],"summary":"Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability","details":"Apple iOS, iPadOS, and watchOS WebKit contain an unspecified vulnerability that allows for universal cross-site scripting (XSS) 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.","categories":["Operating systems"],"product":"iOS, iPadOS, and watchOS","vendor":"Apple","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2021-1879","source_modified_at":"2025-10-21T23:25:49.688Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"iOS and iPadOS","vendor":"Apple","versions":[{"lessThan":"14.4","status":"affected","version":"unspecified","versionType":"custom"}],"defaultStatus":null},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2021-1879","source_modified_at":"2025-10-21T23:25:49.688Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"iOS","vendor":"Apple","versions":[{"lessThan":"12.5","status":"affected","version":"unspecified","versionType":"custom"}],"defaultStatus":null},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2021-1879","source_modified_at":"2025-10-21T23:25:49.688Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"watchOS","vendor":"Apple","versions":[{"lessThan":"7.3","status":"affected","version":"unspecified","versionType":"custom"}],"defaultStatus":null}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2021-1879","source_modified_at":"2025-10-21T23:25:49.688Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"iOS and iPadOS","ecosystem":null},"version":"14.4","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2021-1879","source_modified_at":"2025-10-21T23:25:49.688Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"iOS","ecosystem":null},"version":"12.5","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2021-1879","source_modified_at":"2025-10-21T23:25:49.688Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"watchOS","ecosystem":null},"version":"7.3","basis":"first unaffected version stated in the CVE record"}],"cvss":6.1,"severity":"Medium","kev":{"listed":true,"date_added":"2021-11-03","due_date":"2021-11-17","required_action":"Apply updates per vendor instructions.","ransomware_campaign_use":"Unknown"},"epss":{"probability":0.07082,"percentile":0.94213,"score_date":"2026-10-23"},"published_at":"2021-04-02T18:07:52.000Z","modified_at":"2025-10-21T23:25:49.688Z","provenance":[{"source":"CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23T17:00:09.9001Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2021-1879","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2025-10-21T23:25:49.688Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-1879","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CISA KEV","CVE List","EPSS"],"references":[{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-1879","source":"CISA KEV"},{"source":"CVE List","url":"https://support.apple.com/en-us/HT212256","tags":["x_refsource_MISC","x_transferred"]},{"source":"CVE List","url":"https://support.apple.com/en-us/HT212257","tags":["x_refsource_MISC","x_transferred"]},{"source":"CVE List","url":"https://support.apple.com/en-us/HT212258","tags":["x_refsource_MISC","x_transferred"]},{"source":"CVE List","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1879","tags":["government-resource"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CISA ADP","ssvc":{"exploitation":"active","automatable":"no","technical_impact":"partial","assessed_at":"2025-01-29T17:31:41.503370Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2025-10-21T23:25:49.688Z","content_hash":"740a347dd40d3df743419a5ad25addb164706aba99e6427ce3686bbab8384f36"}}