What’s Vulnerable › Vulnerabilities

CVE-2020-27950: Apple Multiple Products Memory Initialization Vulnerability

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2021-11-03
• EPSS: 16.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-12-08 · updated 2026-06-17
• Weakness: CWE-665

Description

A memory initialization issue was addressed. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.1, iOS 12.4.9, watchOS 6.2.9, Security Update 2020-006 High Sierra, Security Update 2020-006 Mojave, iOS 14.2 and iPadOS 14.2, watchOS 5.3.9, macOS Catalina 10.15.7 Supplemental Update, macOS Catalina 10.15.7 Update. A malicious application may be able to disclose kernel memory.

Affected products

• Apple iPadOS: before 14.2 — fixed in 14.2
• Apple Iphone Os: before 12.4.9; from 14.0 before 14.2 — fixed in 12.4.9, 14.2
• Apple macOS: before 10.15.7; from 11.0 before 11.0.1 — fixed in 10.15.7, 11.0.1
• Apple watchOS: before 5.3.9; from 6.0 before 6.2.9; from 7.0 before 7.1 — fixed in 5.3.9, 6.2.9, 7.1

How to fix

Upgrade to a fixed version: Apple iPadOS 14.2; Apple Iphone Os 12.4.9, 14.2; Apple macOS 10.15.7, 11.0.1; Apple watchOS 5.3.9, 6.2.9, 7.1. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/161296/XNU-Kernel-Mach-Message-Trailers-Memory-Disclosure.html
• http://seclists.org/fulldisclosure/2020/Dec/32
• https://support.apple.com/en-us/HT211928
• https://support.apple.com/en-us/HT211929
• https://support.apple.com/en-us/HT211931
• https://support.apple.com/en-us/HT211940
• https://support.apple.com/en-us/HT211944
• https://support.apple.com/en-us/HT211945
• https://support.apple.com/en-us/HT211946
• https://support.apple.com/en-us/HT211947
• http://packetstormsecurity.com/files/161296/XNU-Kernel-Mach-Message-Trailers-Memory-Disclosure.html
• http://seclists.org/fulldisclosure/2020/Dec/32

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