CVE-2021-30663
Apple Multiple Products WebKit Integer Overflow Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 3.52% probability · 89th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 3 November 2021 · due 17 November 2021
- Weakness
- CWE-190
- Affected
- apple/safari · apple/ipados · apple/iphone os · apple/macos · apple/tvos
- Source
- product-security@apple.com
EPSS 3.5% since 30 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-30663
References
- https://support.apple.com/en-us/HT212335Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212336Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212341Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212532Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212534Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212335Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212336Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212341Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212532Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212534Release Notes, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30663Third Party Advisory, US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.