CVE-2025-24239 is a vulnerability identified in Apple macOS, specifically addressed in macOS Sequoia 15.4. The root cause is a downgrade issue related to code-signing restrictions, which previously allowed applications to bypass certain security checks. Code-signing is a critical security mechanism that ensures only trusted and verified applications can access protected system resources and user data. In this case, the downgrade flaw permitted an application with limited privileges (requiring some level of user authorization but no user interaction) to access protected user data, violating confidentiality without affecting data integrity or system availability. The vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The CVSS v3.1 base score is 6.5, indicating a medium severity level, with the vector AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, meaning the attack can be performed remotely with low complexity, requires privileges but no user interaction, and results in high confidentiality impact. No known exploits have been reported in the wild, but the potential for sensitive data leakage makes this a significant concern. The issue was resolved by enhancing code-signing restrictions in macOS Sequoia 15.4, preventing downgrade attacks that could bypass security controls. Organizations using macOS devices should apply the update promptly to mitigate risk.

The primary impact of CVE-2025-24239 is unauthorized disclosure of protected user data on affected macOS systems. This can lead to exposure of sensitive personal or corporate information, potentially resulting in privacy violations, intellectual property theft, or compliance breaches. Since the vulnerability does not affect data integrity or system availability, it is less likely to cause system outages or data corruption. However, the confidentiality breach alone can have severe consequences, especially for organizations handling sensitive data such as financial institutions, healthcare providers, and government agencies. The ease of exploitation (remote, low complexity, requiring some privileges but no user interaction) increases the risk, particularly in environments where users may run untrusted or malicious applications. The scope includes all macOS systems running versions prior to Sequoia 15.4, which encompasses a large user base globally. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits in the future.

1. Immediately update all macOS devices to macOS Sequoia 15.4 or later, where the vulnerability is fixed. 2. Enforce strict application code-signing policies and restrict installation of unsigned or improperly signed applications through Mobile Device Management (MDM) solutions. 3. Implement least privilege principles to limit user and application privileges, reducing the potential for exploitation. 4. Monitor system logs and application behaviors for unusual access patterns to protected user data. 5. Educate users about the risks of installing untrusted applications and encourage adherence to organizational security policies. 6. Employ endpoint detection and response (EDR) tools capable of identifying anomalous access to sensitive data. 7. Regularly audit installed applications and remove those that are unnecessary or pose security risks. 8. Coordinate with Apple security advisories to stay informed about any updates or emerging threats related to this vulnerability.