CVE-2020-3909: Apple iCloud

Critical severity, CVSS 9.8. EPSS: 3% chance of exploitation in the next 30 days.

A buffer overflow was addressed with improved bounds checking. This issue is fixed in iOS 13.4 and iPadOS 13.4, macOS Catalina 10.15.4, tvOS 13.4, watchOS 6.2, iTunes for Windows 12.10.5, iCloud for Windows 10.9.3, iCloud for Windows 7.18. Multiple issues in libxml2.

Affected products

• Apple iCloud: before 7.18 (fixed in 7.18); from 10.9, before 10.9.3 (fixed in 10.9.3)
• Apple iPadOS: before 13.4 (fixed in 13.4)
• Apple iPhone OS: before 13.4 (fixed in 13.4)
• Apple iTunes: before 12.10.5 (fixed in 12.10.5)
• Apple Mac OS X: before 10.15.4 (fixed in 10.15.4)
• Apple tvOS: before 13.4 (fixed in 13.4)
• Apple watchOS: before 6.2 (fixed in 6.2)
• Oracle Sun ZFS Storage Appliance Kit Software: version 8.8 only

Published 2020-04-01. Last modified 2026-06-17.