Apple Multiple Products WebKit Integer Overflow Vulnerability

HIGH 8.8EXPLOITED (CISA KEV)CVE-2021-30663 · Published 08/09/2021 · updated 17/06/2026

Apple Multiple Products WebKit Integer Overflow 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
safari apple	`< 14.1.1`	`14.1.1`

Description

An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, Safari 14.1.1, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution.

References

support.apple.com/en-us/HT212335 · Release Notes
support.apple.com/en-us/HT212336 · Release Notes
support.apple.com/en-us/HT212341 · Release Notes
support.apple.com/en-us/HT212532 · Release Notes
support.apple.com/en-us/HT212534 · Release Notes
cisa.gov/known-exploited-vulnerabilities-catalog · Third Party Advisory
CISA KEV · CVE-2021-30663

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