What’s Vulnerable › Vulnerabilities

CVE-2020-3909

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-04-01 · updated 2026-06-17
• Weakness: CWE-120

Description

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 for Windows: before 7.18; from 10.9 before 10.9.3 — fixed in 10.9.3, 7.18
• Apple iPadOS: before 13.4 — fixed in 13.4
• Apple Iphone Os: before 13.4 — fixed in 13.4
• Apple iTunes for Windows: before 12.10.5 — fixed in 12.10.5
• macOS: 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: 8.8

How to fix

Upgrade to a fixed version: Apple iCloud for Windows 10.9.3, 7.18; Apple iPadOS 13.4; Apple Iphone Os 13.4; Apple iTunes for Windows 12.10.5; macOS 10.15.4; Apple tvOS 13.4; Apple watchOS 6.2. Check the vendor advisory for mitigations.

References

• https://support.apple.com/HT211100
• https://support.apple.com/HT211101
• https://support.apple.com/HT211102
• https://support.apple.com/HT211103
• https://support.apple.com/HT211105
• https://support.apple.com/HT211106
• https://support.apple.com/HT211107
• https://www.oracle.com/security-alerts/cpuoct2020.html
• https://support.apple.com/HT211100
• https://support.apple.com/HT211101
• https://support.apple.com/HT211102
• https://support.apple.com/HT211103

Get alerted when CVE-2020-3909 or the next vulnerability affects your stack