# CVE-2021-30663: Apple Multiple Products WebKit Integer Overflow Vulnerability

> CVE-2021-30663: Apple Multiple Products WebKit Integer Overflow Vulnerability. CVSS 7.8 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2021-30663
Last updated: 2025-10-21T23:25:34Z

- Published: 2021-09-08 14:49 UTC · Updated: 2025-10-21 23:25 UTC · Assigner: apple
- CVSS: 7.8 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS: 3.5%, 89th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2021-11-03, federal due date 2021-11-17, ransomware use: Unknown

## 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.

## CISA required action

Apply updates per vendor instructions.

## Affected vendors and products

- Apple: macOS

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2021-30663)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2021-30663)
- [https://support.apple.com/en-us/HT212335](https://support.apple.com/en-us/HT212335)
- [https://support.apple.com/en-us/HT212336](https://support.apple.com/en-us/HT212336)
- [https://support.apple.com/en-us/HT212341](https://support.apple.com/en-us/HT212341)
- [https://support.apple.com/en-us/HT212532](https://support.apple.com/en-us/HT212532)
- [https://support.apple.com/en-us/HT212534](https://support.apple.com/en-us/HT212534)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2021-30663 · Markdown: https://rewindex.com/cve/CVE-2021-30663.md · JSON: https://rewindex.com/api/v1/cves/CVE-2021-30663 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T04:03:30.793Z