CVE-2025-43476 is a vulnerability in Apple macOS stemming from a permissions issue that allows an application to escape its sandbox environment. Sandboxing is a critical security mechanism that restricts applications to a limited set of resources and capabilities, preventing them from accessing or modifying system components or other apps' data. This vulnerability, classified under CWE-284 (Improper Access Control), undermines this containment by permitting an app to break out of its sandbox, potentially gaining unauthorized access to system resources and sensitive information. The issue was addressed by Apple through additional restrictions implemented in macOS Sequoia 15.7.2, macOS Tahoe 26.1, and macOS Sonoma 14.8.2. The vulnerability requires local access and user interaction to exploit but does not require prior privileges, making it accessible to a broader range of threat actors. The CVSS v3.1 score of 7.8 indicates a high severity, with a vector string AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, meaning the attack requires local access and user interaction but no privileges, and can impact confidentiality, integrity, and availability significantly. Although no known exploits are currently reported in the wild, the potential for malicious apps to bypass sandbox restrictions poses a serious risk, especially in environments where untrusted or third-party applications are installed. This vulnerability could be leveraged to execute arbitrary code with escalated privileges, access sensitive data, or disrupt system operations. Organizations relying on macOS devices should prioritize updating to the patched versions to mitigate this risk.

For European organizations, this vulnerability presents a significant risk to the security of macOS endpoints. The ability for an app to escape its sandbox can lead to unauthorized access to sensitive corporate data, intellectual property, and user credentials. It can also facilitate the deployment of persistent malware or ransomware, compromising system integrity and availability. Sectors such as finance, healthcare, government, and technology, which often use macOS devices and handle sensitive information, are particularly vulnerable. The local attack vector means that insider threats or social engineering attacks that trick users into running malicious apps could exploit this vulnerability. The lack of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits once the vulnerability details are widely known. Failure to patch promptly could lead to targeted attacks against European organizations, potentially resulting in data breaches, operational disruption, and reputational damage.

European organizations should immediately verify the macOS versions deployed across their endpoints and prioritize upgrading to macOS Sequoia 15.7.2, macOS Tahoe 26.1, or macOS Sonoma 14.8.2, where the vulnerability is fixed. Beyond patching, organizations should enforce strict application control policies, limiting installation to trusted sources such as the Apple App Store and verified enterprise apps. Implement endpoint detection and response (EDR) solutions capable of monitoring for anomalous app behavior indicative of sandbox escapes. Educate users about the risks of installing untrusted applications and the importance of not interacting with suspicious prompts or software. Employ least privilege principles to reduce the impact of any local compromise and consider network segmentation to contain potential breaches. Regularly audit and review macOS security configurations and logs to detect early signs of exploitation attempts. Finally, maintain an updated inventory of macOS devices and ensure timely deployment of security updates as part of a robust patch management process.