CVE-2025-43266 is a sandbox escape vulnerability in Apple macOS identified as a permissions issue (CWE-732) that could allow a malicious or compromised application to break out of its restricted execution environment. Sandboxing is a critical security mechanism in macOS that isolates applications to limit their access to system resources and user data. This vulnerability undermines that isolation by improperly restricting permissions, potentially enabling an app to access or modify resources beyond its intended scope. The flaw affects multiple macOS versions prior to the patched releases: Sequoia 15.6, Sonoma 14.7.7, and Ventura 13.7.7. The CVSS 3.1 base score is 5.1 (medium severity), with an attack vector of local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and limited confidentiality and integrity impact (C:L/I:L/A:N). This means an attacker with local access but no special privileges could exploit the vulnerability without user interaction, potentially gaining unauthorized access to data or modifying it outside the sandbox. No known exploits are currently reported in the wild, indicating limited active threat but a potential risk if weaponized. The vulnerability was addressed by Apple through additional permission restrictions in the specified macOS updates, reinforcing sandbox boundaries to prevent escape. Organizations relying on macOS sandboxing for security should consider this vulnerability significant because sandbox escapes can lead to broader system compromise or data leakage. The lack of requirement for user interaction or privileges increases the risk in multi-user or shared device environments. However, the local attack vector limits remote exploitation scenarios.

For European organizations, the primary impact of CVE-2025-43266 lies in the potential compromise of application sandboxing, which is a foundational security control in macOS environments. If exploited, malicious apps or attackers with local access could bypass sandbox restrictions, leading to unauthorized access to sensitive data or modification of system or user files outside the sandbox. This could undermine data confidentiality and integrity, especially in sectors handling sensitive personal data (e.g., finance, healthcare, government). The vulnerability does not directly affect availability, but sandbox escapes can be a stepping stone for further attacks that might impact system stability or availability. European organizations using macOS in enterprise, government, or critical infrastructure contexts could face increased risk if patching is delayed or if local access controls are weak. The medium severity rating suggests a moderate but non-trivial risk, emphasizing the importance of timely patching and monitoring. Since no exploits are currently known in the wild, the immediate threat is limited, but the vulnerability could be targeted in future attacks, particularly by advanced threat actors seeking to escalate privileges or move laterally within macOS environments.

1. Apply the latest macOS updates immediately: macOS Sequoia 15.6, Sonoma 14.7.7, and Ventura 13.7.7 contain the fix for this vulnerability and should be deployed across all affected systems without delay. 2. Enforce strict local access controls and user permissions to reduce the risk of local exploitation, including limiting administrative privileges and using endpoint protection solutions that monitor for suspicious app behavior. 3. Review and tighten sandbox policies and configurations for applications, especially those handling sensitive data or running with elevated privileges. 4. Implement application whitelisting to prevent unauthorized or untrusted applications from executing on macOS devices. 5. Monitor system logs and security telemetry for unusual activity that could indicate attempts to escape sandbox restrictions or escalate privileges. 6. Educate users about the risks of installing untrusted applications and enforce policies restricting software installation to trusted sources. 7. Consider deploying endpoint detection and response (EDR) tools capable of detecting anomalous behaviors related to sandbox escape attempts. 8. Regularly audit macOS systems for compliance with security baselines and update configurations as needed to maintain robust sandbox enforcement.