CVE-2025-43406 is a logic-based vulnerability identified in Apple macOS that permits an application with limited privileges to access sensitive user data improperly. The root cause is a logic issue in the operating system's access control mechanisms, which failed to enforce adequate restrictions on data access by local applications. This vulnerability does not require user interaction to be exploited, but it does require the attacker to have local privileges on the affected system. The flaw does not allow modification or deletion of data (integrity unaffected) nor does it impact system availability. The CVSS v3.1 base score is 5.5 (medium severity), reflecting the high confidentiality impact but limited attack vector (local) and requirement for privileges. Apple resolved this issue in macOS Tahoe 26.1 by enhancing the restrictions that govern access to sensitive user data, thereby preventing unauthorized access by local applications. No public exploits have been reported, and the vulnerability was reserved in April 2025 and published in December 2025. The CWE classification CWE-497 indicates a logic error related to information exposure. This vulnerability underscores the importance of strict access control enforcement in multi-user operating systems to prevent data leakage from less privileged applications.

The primary impact of CVE-2025-43406 is unauthorized disclosure of sensitive user data on affected macOS systems. This can lead to privacy violations, leakage of confidential information, and potential secondary attacks if sensitive data such as credentials or personal information are exposed. Organizations relying on macOS for critical operations, especially those with multiple users or untrusted local applications, face increased risk of insider threats or malware exploiting this flaw to harvest data. Although the vulnerability does not affect data integrity or system availability, the confidentiality breach alone can result in regulatory compliance issues, reputational damage, and financial losses. The requirement for local access limits remote exploitation but does not eliminate risk in environments where endpoint security is weak or users may inadvertently install malicious software. The absence of known exploits reduces immediate risk but does not preclude future weaponization.

To mitigate CVE-2025-43406, organizations should promptly update all macOS systems to version Tahoe 26.1 or later, where the vulnerability is patched. Beyond patching, implement strict application whitelisting and endpoint protection to prevent installation or execution of untrusted local applications. Employ least privilege principles to limit user and application permissions, reducing the attack surface for local privilege exploitation. Regularly audit local user accounts and installed software to detect unauthorized or suspicious activity. Use macOS security features such as System Integrity Protection (SIP) and sandboxing to further restrict application capabilities. Educate users about the risks of installing unverified software and enforce policies that minimize local administrative access. For high-security environments, consider additional monitoring for anomalous access to sensitive data and use data encryption to protect information at rest. Finally, maintain an incident response plan that includes procedures for addressing potential data exposure incidents stemming from local vulnerabilities.