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.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

No CVSS v3.0

Access Vector Network

Access Complexity Medium

Authentication None

Confidentiality Impact Partial

Integrity Impact Partial

Availability Impact Partial

This CVE is in the KEV database since Nov. 3, 2021.

Exploitation active

Automatable no

Technical Impact total

Affected Vendors & Products

Vendors Products
Apple
  • Ipados
  • Iphone Os
  • Macos
  • Safari
  • Tvos
Redhat
  • Enterprise Linux
  • Rhel Els

Configuration 1 [-]

OR cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
Package CPE Advisory Released Date
Red Hat Enterprise Linux 7 Extended Lifecycle Support
webkitgtk4-0:2.48.3-2.el7_9 cpe:/o:redhat:rhel_els:7 RHSA-2025:10364 2025-07-07T00:00:00Z
Red Hat Enterprise Linux 8
webkit2gtk3-0:2.32.3-2.el8 cpe:/a:redhat:enterprise_linux:8 RHSA-2021:4381 2021-11-09T00:00:00Z
References
Link Providers
https://nvd.nist.gov/vuln/detail/CVE-2021-30663 cve-icon
https://support.apple.com/en-us/HT212335 cve-icon cve-icon
https://support.apple.com/en-us/HT212336 cve-icon cve-icon
https://support.apple.com/en-us/HT212341 cve-icon cve-icon
https://support.apple.com/en-us/HT212532 cve-icon cve-icon
https://support.apple.com/en-us/HT212534 cve-icon cve-icon
https://webkitgtk.org/security/WSA-2021-0004.html cve-icon
https://www.cisa.gov/known-exploited-vulnerabilities-catalog cve-icon
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30663 cve-icon
https://www.cve.org/CVERecord?id=CVE-2021-30663 cve-icon
History

Wed, 22 Oct 2025 00:30:00 +0000

Type Values Removed Values Added
References

Tue, 21 Oct 2025 20:30:00 +0000

Type Values Removed Values Added
References

Tue, 21 Oct 2025 19:30:00 +0000

Type Values Removed Values Added
References

Mon, 07 Jul 2025 14:00:00 +0000

Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els

Fri, 14 Feb 2025 16:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:apple:macos:*:*:*:*:*:*:*:* cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*

Tue, 04 Feb 2025 17:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

 cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'active', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Mon, 03 Feb 2025 14:15:00 +0000

Type Values Removed Values Added
Metrics kev

{'dateAdded': '2021-11-03'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Wed, 14 Aug 2024 00:45:00 +0000

Type Values Removed Values Added
References
cve-icon MITRE

Status: PUBLISHED

Assigner: apple

Published: 2021-09-08T14:49:41.000Z

Updated: 2025-10-21T23:25:34.065Z

Reserved: 2021-04-13T00:00:00.000Z

Link: CVE-2021-30663

cve-icon Vulnrichment

Updated: 2024-08-03T22:40:32.148Z

cve-icon NVD

Status : Analyzed

Published: 2021-09-08T15:15:13.413

Modified: 2025-10-23T14:55:43.020

Link: CVE-2021-30663

cve-icon Redhat

Severity : Moderate

Publid Date: 2021-07-28T00:00:00Z

Links: CVE-2021-30663 - Bugzilla