Apple iOS, iPadOS, and watchOS
YES - ON THE CISA KEV LIST
CVE-2021-1879
Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability
overdue since 2021-11-17
Apple: 96 entries (5.4% of all KEV entries are from this vendor); 10 added in 2026.
BOD 26-04 note: this is the date printed in the CISA catalog. A federal agency's actual deadline is set by its SSVC tier - Act (3 days), Attend (14 days), Track (60 days), or the next scheduled upgrade - counted from the KEV listing date or the date the vulnerability is identified in its environment, whichever comes first. Use the tier helper on each CVE page for your own window.
Your BOD 26-04 window (SSVC tier helper)
Your remediation window ends:
Description
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.
Required action (CISA)
Apply updates per vendor instructions.
Notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1879
References
Other KEV entries for this vendor: Apple
- CVE-2024-27834 - Multiple Products (2026-11-04)
- CVE-2026-86950 - Multiple Products (2026-09-29)
- CVE-2026-65400 - macOS (2026-08-18)
- CVE-2025-43510 - Multiple Products (2026-03-20)
- CVE-2025-43520 - Multiple Products (2026-03-20)
- CVE-2025-31277 - Multiple Products (2026-03-20)
- CVE-2023-43000 - Multiple Products (2026-03-05)
- CVE-2021-30952 - Multiple Products (2026-03-05)
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