CVE-2021-1879
CISA KEVPublished November 3, 2021 · Updated April 3, 2026
high
Official 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.
Affected Products
| Vendor | Product |
|---|---|
| Apple | iOS, iPadOS, and watchOS |
Patch Status
Patch by 2021-11-17
Recommended Actions
- Check if your systems use any of the affected products listed above.
- Apply vendor patches immediately if available.
- This vulnerability is in CISA's Known Exploited Vulnerabilities catalog — prioritize remediation.
- Monitor vendor advisories for updates and additional mitigations.
- Review logs for indicators of compromise related to CVE-2021-1879.