CVE-2026-20630 is a permissions vulnerability in Apple macOS identified as CWE-277 (Improper Access Control). The issue arises from insufficient restrictions on app permissions, allowing an application with low privileges (PR:L) and no required user interaction (UI:N) to access protected user data, thereby compromising confidentiality (C:H) without affecting integrity or availability. The attack vector is local (AV:L), meaning an attacker must have local access to the system, but the access complexity is low (AC:L), indicating the exploit does not require advanced conditions. The vulnerability affects unspecified macOS versions prior to the release of macOS Tahoe 26.3, where Apple implemented additional permission restrictions to address the flaw. Although no known exploits are reported in the wild, the vulnerability poses a risk to user data confidentiality, especially in environments where untrusted or malicious applications could be installed or executed. The CVSS 3.1 base score is 5.5, reflecting a medium severity level. The vulnerability does not require user interaction and does not impact data integrity or system availability, focusing solely on unauthorized data access. This flaw highlights the importance of strict access control enforcement in operating system design to prevent unauthorized data exposure.

The primary impact of CVE-2026-20630 is unauthorized access to protected user data on affected macOS systems. This can lead to exposure of sensitive personal or corporate information, potentially resulting in privacy violations, data leakage, or intellectual property theft. Since the vulnerability does not affect data integrity or availability, it does not enable data modification or system disruption. However, the confidentiality breach alone can have serious consequences, especially for organizations handling sensitive or regulated data. Attackers with local access but limited privileges could exploit this flaw to escalate their data access capabilities without alerting the user. This risk is particularly relevant in environments where multiple users share devices, or where malware or malicious insiders have limited system access. The absence of required user interaction lowers the barrier for exploitation once local access is obtained. Although no active exploitation is currently known, the vulnerability could be leveraged in targeted attacks against high-value macOS users or organizations. Failure to apply the patch could expose enterprises to data breaches and compliance violations.

To mitigate CVE-2026-20630, organizations and users should promptly update affected macOS systems to version Tahoe 26.3 or later, where Apple has implemented additional permission restrictions to fix the issue. Beyond patching, organizations should enforce strict application control policies to limit installation and execution of untrusted or unauthorized apps, reducing the risk of local exploitation. Employ endpoint security solutions capable of detecting anomalous app behavior and privilege escalations. Regularly audit user permissions and system access controls to ensure least privilege principles are maintained. For shared or multi-user environments, consider additional user session isolation and data protection mechanisms. Educate users about the risks of installing unverified software and maintain robust physical security to prevent unauthorized local access. Monitoring system logs for unusual access patterns to protected data can help detect potential exploitation attempts. Finally, integrate this vulnerability into vulnerability management and incident response workflows to ensure timely detection and remediation.