CVE-2026-20651 is a privacy vulnerability identified in Apple macOS that stems from improper handling of temporary files, categorized under CWE-377 (Insecure Temporary File). This flaw allows a local application to access sensitive user data that it should not be authorized to read. The vulnerability affects multiple macOS versions prior to the patched releases: macOS Sequoia 15.7.5, macOS Sonoma 14.8.4, and macOS Tahoe 26.3. The root cause involves inadequate safeguards around temporary file creation and management, which can lead to unauthorized file access by malicious or compromised applications. The CVSS v3.1 base score is 6.2, with vector AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, indicating that exploitation requires local access but no privileges or user interaction, and the impact is high on confidentiality only. There are no known exploits in the wild at this time. Apple mitigated the issue by enhancing the handling of temporary files to prevent unauthorized access to sensitive data. This vulnerability highlights the risks associated with temporary file management in operating systems and the importance of secure file handling practices.

The primary impact of CVE-2026-20651 is the unauthorized disclosure of sensitive user data on affected macOS systems. Since the vulnerability allows local applications to access data they should not, it poses a significant privacy risk, especially in environments where multiple users or untrusted applications coexist. Confidentiality is compromised, which could lead to leakage of personal information, credentials, or other sensitive content. However, the vulnerability does not affect data integrity or system availability. The requirement for local access limits the attack surface to users or applications already present on the system, reducing the risk of remote exploitation. Nonetheless, in enterprise or shared computing environments, malicious insiders or compromised applications could exploit this flaw to escalate data access. The absence of known exploits in the wild suggests limited current exploitation, but the presence of a reliable vulnerability with a medium severity score warrants prompt remediation to prevent potential abuse.

To mitigate CVE-2026-20651, organizations and users should promptly apply the security updates released by Apple for macOS Sequoia 15.7.5, Sonoma 14.8.4, and Tahoe 26.3. Beyond patching, administrators should enforce strict application control policies to limit the installation and execution of untrusted or unnecessary applications, reducing the risk of local exploitation. Employing endpoint detection and response (EDR) solutions can help monitor for suspicious local file access patterns indicative of exploitation attempts. Additionally, users should be educated about the risks of installing unverified software and the importance of maintaining updated systems. For environments with sensitive data, implementing file system permissions and sandboxing mechanisms can further restrict application access to temporary files. Regular audits of temporary file usage and cleanup policies can also reduce exposure. Finally, organizations should maintain robust access controls and user privilege management to limit local access to trusted users only.