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

MEDIUM 6.1EXPLOITED (CISA KEV)CVE-2021-1879 · Published 02/04/2021 · updated 17/06/2026

Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 03/11/2021. Patch affected systems as an emergency.

Package	Affected versions	Patched versions
iOS, iPadOS, and watchOS Apple	Versions not published yet (product named by CISA KEV)

Description

This issue was addressed by improved management of object lifetimes. This issue is fixed in iOS 12.5.2, iOS 14.4.2 and iPadOS 14.4.2, watchOS 7.3.3. Processing maliciously crafted web content may lead to universal cross site scripting. Apple is aware of a report that this issue may have been actively exploited..

References

support.apple.com/en-us/HT212256 · Release Notes
support.apple.com/en-us/HT212257 · Release Notes
support.apple.com/en-us/HT212258 · Release Notes
cisa.gov/known-exploited-vulnerabilities-catalog · US Government Resource
CISA KEV · CVE-2021-1879

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