CVE-2020-9991: Apple iCloud

High severity, CVSS 7.5. EPSS: 2.8% chance of exploitation in the next 30 days.

This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.0, iOS 14.0 and iPadOS 14.0, iCloud for Windows 7.21, tvOS 14.0. A remote attacker may be able to cause a denial of service.

Affected products

• Apple iCloud: before 7.21 (fixed in 7.21); from 11.0, before 11.4 (fixed in 11.4)
• Apple iPadOS: before 14.0 (fixed in 14.0)
• Apple iPhone OS: before 14.0 (fixed in 14.0)
• Apple Mac OS X: before 11.0.1 (fixed in 11.0.1)
• Apple tvOS: before 14.0 (fixed in 14.0)
• Apple watchOS: before 7.0 (fixed in 7.0)

Published 2020-12-08. Last modified 2026-06-17.