Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability
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.
- Vendor
- Apple
- Product
- iOS, iPadOS, and watchOS
- CVSS
- 6.1
- EPSS (exploit probability)
- 7.1%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2021-1879 being exploited?
Yes. CISA added CVE-2021-1879 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 7.1% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-10-21. Full cross-catalog view: /kev-comparison
What to do
CISA required actionApply updates per vendor instructions.
US federal civilian agencies must remediate by (14 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Apple iOS, iPadOS, and watchOS CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2023-41061 Apple iOS, iPadOS, and watchOS Wallet Code Execution Vulnerability | [ HIGH ] | 7.8 | 4.4% | |
| CVE-2020-9819 Apple iOS, iPadOS, and watchOS Memory Corruption Vulnerability | [ MEDIUM ] | 4.3 | 2.2% | |
| CVE-2020-9818 Apple iOS, iPadOS, and watchOS Out-of-Bounds Write Vulnerability | [ HIGH ] | 8.8 | 2.3% |