Apple · Multiple Products
CVE-2020-27950
Apple Multiple Products Memory Initialization Vulnerability
What it is
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.
CISA: Apple iOS, iPadOS, macOS, and watchOS contain a memory initialization vulnerability that may allow a malicious application to disclose kernel memory.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: May 3, 2022
- Added to the CISA list
- November 3, 2021
- Published
- December 8, 2020
- Severity
- Medium 5.5 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 17% in the top 3.0% of all known vulnerabilities
- Weakness
- CWE-665
- More details
- NVD · CVE.org · CISA
All references (10)
- https://support.apple.com/en-us/HT211931
- https://support.apple.com/en-us/HT211928
- https://support.apple.com/en-us/HT211929
- 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://seclists.org/fulldisclosure/2020/Dec/32
- http://packetstormsecurity.com/files/161296/XNU-Kernel-Mach-Message-Trailers-Memory-Disclosure.html
More exploited flaws from Apple
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Sep 29, 2026 | Out-of-Bounds Write | Multiple Products | High 8.8 | 26% |
| Mar 20, 2026 | Buffer Overflow | Multiple Products | High 8.8 | 1.7% |
| Mar 20, 2026 | Improper Locking | Multiple Products | High 7.8 | 0.4% |
| Mar 20, 2026 | Classic Buffer Overflow | Multiple Products | Medium 5.5 | 0.4% |
| Mar 5, 2026 | Integer Overflow or Wraparound | Multiple Products | High 8.8 | 7.0% |
| Mar 5, 2026 | Use-After-Free | Multiple Products | High 8.8 | 4.0% |
| Feb 12, 2026 | Multiple Buffer Overflow | Multiple Products | High 7.8 | 1.7% |
| Dec 15, 2025 | Use-After-Free WebKit | Multiple Products | High 8.8 | 26% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.