CVE-2021-30688: 
macOS vulnerability analysis and mitigation

CVE-2021-30688 is a path handling vulnerability discovered in Apple's macOS App Store component that allows a malicious application to break out of its sandbox. The vulnerability was fixed in macOS Big Sur 11.4 and Security Update 2021-003 Catalina, released on May 24, 2021. The vulnerability was discovered by Thijs Alkemade of Computest Research Division (Apple Advisory).

The vulnerability stems from a path handling issue in the App Store component of macOS. Apple addressed this vulnerability by improving validation of paths. The vulnerability has been assigned a CVSS v3.1 base score of 8.8 (HIGH) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, indicating local access required with low attack complexity and no user interaction needed (NVD).

If exploited, this vulnerability allows a malicious application to break out of its sandbox environment, potentially gaining access to resources and data that should be restricted. This represents a significant security boundary bypass that could lead to unauthorized access to system resources (Apple Advisory).

Apple has released patches to address this vulnerability in macOS Big Sur 11.4 and Security Update 2021-003 Catalina. Users are advised to update their systems to these versions or later to mitigate the vulnerability (Apple Advisory, Apple Advisory).