CVE-2026-20603 is a vulnerability identified in Apple macOS that allows an application running with root privileges to access private information that should otherwise be protected. The root cause stems from insufficient redaction of sensitive data within the operating system, which means that privileged applications can bypass intended data protection mechanisms. This vulnerability was addressed by Apple in macOS Tahoe 26.3 through improved redaction techniques that prevent unauthorized access to private information. The vulnerability is classified under CWE-284, indicating an authorization issue where access control is improperly enforced. The CVSS v3.1 base score is 4.4, with the vector indicating that the attack requires local access (AV:L), low attack complexity (AC:L), high privileges (PR:H), no user interaction (UI:N), unchanged scope (S:U), high confidentiality impact (C:H), and no impact on integrity or availability (I:N/A:N). There are no known exploits in the wild, and the affected versions are unspecified, but the fix is included in macOS Tahoe 26.3. This vulnerability primarily affects environments where applications run with root privileges, which could include system utilities, management tools, or malicious software that has escalated privileges. The issue highlights the importance of robust data redaction and access control even for highly privileged processes.

The primary impact of CVE-2026-20603 is the potential unauthorized disclosure of sensitive information on macOS systems. Since exploitation requires root privileges and local access, the risk is somewhat limited to scenarios where an attacker or malicious application already has elevated access. However, once exploited, the attacker can access private data that should be protected, potentially leading to privacy violations, leakage of confidential information, or aiding further attacks. The vulnerability does not affect system integrity or availability, so it does not allow modification or disruption of system operations. Organizations with macOS deployments, especially those running applications with root privileges or allowing third-party software with elevated rights, are at risk. This could impact enterprises, government agencies, and individuals relying on macOS for sensitive workloads. The lack of known exploits reduces immediate risk, but the presence of a fix indicates the vulnerability is credible and should be addressed promptly to prevent future exploitation.

To mitigate CVE-2026-20603, organizations should promptly update all affected macOS systems to macOS Tahoe 26.3 or later, which includes the fix for improved redaction of sensitive information. Additionally, review and audit applications and services running with root privileges to ensure they are necessary and trustworthy, minimizing the attack surface. Implement strict access controls and monitoring for privilege escalation attempts on macOS endpoints. Employ endpoint detection and response (EDR) solutions capable of detecting anomalous behavior from root-level processes. Limit the number of users and applications granted root privileges and enforce the principle of least privilege. Regularly review system logs for unusual access patterns to sensitive data. Consider deploying macOS security features such as System Integrity Protection (SIP) and Full Disk Encryption (FileVault) to further protect data confidentiality. Finally, maintain an up-to-date inventory of macOS versions in use to ensure timely patch management.