CVE-2026-20629 is a privacy vulnerability in Apple macOS identified as a flaw in the handling of temporary files, which could allow a malicious application to access user-sensitive data improperly stored or exposed through these files. The root cause relates to CWE-922, which involves insufficient control over temporary file generation, potentially leading to unauthorized data disclosure. The vulnerability was addressed in macOS Tahoe 26.3 by improving the management and security of temporary files, preventing unauthorized access by apps. The CVSS 3.1 base score is 5.5 (medium), with an attack vector of local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), high confidentiality impact (C:H), and no impact on integrity or availability (I:N/A:N). This indicates that an attacker must have local access and trick the user into interacting with a malicious app to exploit the vulnerability, which then could read sensitive user data that should have been protected. No known exploits have been reported in the wild, but the vulnerability poses a privacy risk, especially in environments where sensitive data is handled on macOS devices. The lack of integrity and availability impact means the threat is confined to data confidentiality breaches rather than system compromise or denial of service.

The primary impact of CVE-2026-20629 is the unauthorized disclosure of sensitive user data on affected macOS systems. This can lead to privacy violations, potential leakage of personal or corporate confidential information, and subsequent risks such as identity theft, corporate espionage, or regulatory non-compliance. Since exploitation requires local access and user interaction, the risk is higher in environments where users may install untrusted applications or be subject to social engineering attacks. Organizations relying heavily on macOS devices for sensitive operations, including enterprises, government agencies, and technology firms, could face data breaches impacting user trust and legal liabilities. Although no integrity or availability impact exists, the confidentiality breach alone can have significant reputational and financial consequences. The absence of known exploits reduces immediate risk but does not eliminate the need for prompt remediation.

To mitigate CVE-2026-20629, organizations should: 1) Immediately update all macOS devices to macOS Tahoe 26.3 or later, where the vulnerability is fixed. 2) Enforce strict application installation policies, allowing only trusted and vetted apps to reduce the risk of malicious apps exploiting this flaw. 3) Educate users about the risks of installing untrusted software and the importance of avoiding suspicious prompts requiring interaction. 4) Implement endpoint protection solutions capable of detecting anomalous local app behaviors that attempt to access sensitive files or temporary directories. 5) Use macOS security features such as System Integrity Protection (SIP) and sandboxing to limit app capabilities. 6) Regularly audit and monitor file system access logs to detect unusual access patterns to temporary files. 7) Employ data loss prevention (DLP) tools to monitor and control sensitive data exposure on endpoints. These targeted measures go beyond generic patching by focusing on reducing attack surface and early detection of exploitation attempts.