A malicious application may be able to execute arbitrary code with kernel privileges. This issue is fixed in macOS Big Sur 11.4, Security Update 2021-003 Catalina, Security Update 2021-004 Mojave. An out-of-bounds write issue was addressed with improved bounds checking.
https://support.apple.com/en-us/HT212530
Source: MITRE
Published: 2021-09-08
Updated: 2021-09-22
Type: CWE-787
Base Score: 9.3
Vector: AV:N/AC:M/Au:N/C:C/I:C/A:C
Impact Score: 10
Exploitability Score: 8.6
Severity: HIGH
Base Score: 7.8
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 1.8
Severity: HIGH