CVE-2021-30663
Apple Multiple Products WebKit Integer Overflow Vulnerability
Published Sep 8, 2021 · updated Jun 16, 2026 · apple safari
Apple iOS, iPadOS, macOS, tvOS, and Safari WebKit contain an integer overflow vulnerability that leads to code execution 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.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Sep 8, 2021 · Catalog
Detected
Apple iOS, iPadOS, macOS, tvOS, and Safari WebKit contain an integer overflow vulnerability that leads to code execution 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.
Nov 3, 2021 · CISA KEV
Known exploited
Apply updates per vendor instructions.
Nov 17, 2021 · CISA KEV
Remediation due
Apply updates per vendor instructions.
Jun 16, 2026 · Catalog
Updated
Apple iOS, iPadOS, macOS, tvOS, and Safari WebKit contain an integer overflow vulnerability that leads to code execution 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.
Required action
Apply updates per vendor instructions.
CISA due date Nov 17, 2021
Affected
- cpe apple/ipadosversion unspecified
- cpe apple/iphone osversion unspecified
- cpe apple/macosversion unspecified
- cpe apple/safariversion unspecified
- cpe apple/tvosversion unspecified
- vendor Apple Multiple Productsversion unspecified
Sources
- CISA KEVConfirmed exploitationCVE-2021-30663
Apple iOS, iPadOS, macOS, tvOS, and Safari WebKit contain an integer overflow vulnerability that leads to code execution 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.
cisa.gov - CVE.orgVulnerability recordCVE-2021-30663
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2021-30663
30-day exploitation probability 3.5%
first.org - NIST NVDVulnerability recordCVE-2021-30663
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.
nvd.nist.gov