CISA-confirmed known exploited vulnerability

CVE-2021-1879

Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability

Apple · iOS, iPadOS, and watchOS

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.

Added to CISA KEV: 2021-11-03

Ransomware campaign use: Unknown

CISA due date: 2021-11-17

Defensive guidance from CISA

Apply updates per vendor instructions.

This is the source's required-action field, not an independently validated patch procedure. Refer to the vendor for exact affected versions and fixes.

Source catalog date: 2026-11-06T19:44:45.1797Z · Last retrieved: 2026-11-06 21:02:26 UTC

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