CVE-2021-30681: 
macOS vulnerability analysis and mitigation

CVE-2021-30681 is a validation issue in the handling of symlinks that affected multiple Apple operating systems including iOS 14.6, iPadOS 14.6, macOS Big Sur 11.4, Security Update 2021-004 Mojave, Security Update 2021-003 Catalina, and watchOS 7.5. The vulnerability was discovered by Zhongcheng Li (CK01) and was fixed in May 2021 through security updates released by Apple (Apple Advisory).

The vulnerability exists in Core Services component and stems from improper validation of symlinks. The issue has a CVSS v3.1 base score of 7.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, indicating local access vector, low attack complexity, no privileges required, and user interaction required (NVD).

When exploited, this vulnerability allows a malicious application to gain root privileges on the affected system. This means an attacker could potentially execute arbitrary code with elevated privileges, leading to complete system compromise (Apple Advisory).

Apple addressed this vulnerability by improving the validation of symlinks in security updates released on May 24, 2021. Users should update to iOS 14.6, iPadOS 14.6, macOS Big Sur 11.4, Security Update 2021-004 Mojave, Security Update 2021-003 Catalina, or watchOS 7.5 to protect against this vulnerability (Apple Advisory).