CVE-2020-27950

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.

Weakness

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable’s type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

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