CVE-2021-1840: 
macOS vulnerability analysis and mitigation

CVE-2021-1840 is a memory corruption vulnerability discovered in the macOS Kernel that was disclosed and patched by Apple in April 2021. The vulnerability affects multiple versions of macOS including Big Sur, Catalina, and Mojave. The issue was discovered by Zuozhi Fan of Ant Group Tianqiong Security Lab (Apple Security, Apple Catalina, Apple Mojave).

The vulnerability stems from a memory corruption issue in the macOS Kernel that was addressed with improved validation. It has been assigned a CVSS v3.1 base score of 7.8 (HIGH) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, indicating local access required with low attack complexity (NVD).

If successfully exploited, this vulnerability allows a local attacker to elevate their privileges on the affected system. The high CVSS score reflects the potential for complete compromise of confidentiality, integrity, and availability of the targeted system (NVD, Rapid7).

Apple has released patches for this vulnerability in macOS Big Sur 11.3, Security Update 2021-002 Catalina, and Security Update 2021-003 Mojave. Users are advised to update their systems to these versions to mitigate the vulnerability (Apple Security, Apple Catalina, Apple Mojave).