CVE-2025-43470 is a permissions vulnerability in Apple macOS that allows a standard user to access and view files originating from a disk image owned by an administrator. The root cause is an insufficient restriction on file permissions when mounting or accessing disk images, which leads to unauthorized read access by lower-privileged users. This vulnerability is categorized under CWE-732, which relates to incorrect permission assignment. The issue was identified and resolved in macOS Tahoe 26.1 by applying stricter permission controls to disk images and their contents, ensuring that standard users cannot bypass intended access controls. The vulnerability requires local access with standard user privileges but does not require user interaction or elevated privileges, making it easier to exploit in multi-user environments. The CVSS v3.1 base score is 5.5 (medium severity), reflecting the high impact on confidentiality but no impact on integrity or availability. No known public exploits exist yet, but the vulnerability poses a risk of unauthorized data disclosure, particularly in environments where sensitive administrator data is stored in disk images accessible on shared machines.

The primary impact of CVE-2025-43470 is unauthorized disclosure of sensitive information. Standard users on affected macOS systems can access files from disk images owned by administrators, potentially exposing confidential data such as credentials, configuration files, or proprietary information. This breach of confidentiality could facilitate further attacks, including social engineering or privilege escalation attempts. While the vulnerability does not affect system integrity or availability, the exposure of sensitive files can undermine organizational security policies and compliance requirements. Organizations with shared macOS environments, such as enterprises, educational institutions, or development teams, are at higher risk. The vulnerability could also impact cloud or virtualized macOS instances where multiple users share the same system. Although no active exploitation is reported, the ease of exploitation without user interaction increases the urgency for remediation to prevent potential insider threats or lateral movement by malicious actors.

To mitigate CVE-2025-43470, organizations should promptly update all affected macOS systems to version Tahoe 26.1 or later, where the vulnerability is fixed. In environments where immediate patching is not feasible, administrators should restrict standard user access to systems where sensitive disk images are stored or mounted. Implement strict access controls and auditing on disk image files to monitor unauthorized access attempts. Consider encrypting sensitive disk images with strong passwords or using FileVault to protect data at rest. Educate users about the risks of mounting disk images from untrusted sources and enforce least privilege principles to minimize the number of users with access to administrator-owned disk images. Regularly review and harden file system permissions and employ endpoint detection tools to identify anomalous access patterns. Additionally, segregate user roles and data to reduce the risk of cross-user data exposure on shared machines.