CVE-2025-43204 is a vulnerability identified in Apple macOS that enables an application to break out of its sandbox. Sandboxing is a critical security mechanism that restricts applications to a limited environment, preventing them from accessing or modifying system resources or other applications. This vulnerability arises from a flaw in the sandbox enforcement code, which Apple has addressed by removing the vulnerable code in macOS Tahoe 26. The vulnerability is classified under CWE-284 (Improper Access Control), indicating that the sandbox boundaries can be bypassed, allowing unauthorized access to system resources. The CVSS 3.1 base score is 7.8, with vector 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 lead to high impact on confidentiality, integrity, and availability. Although the affected macOS versions are unspecified, it is clear that systems not updated to macOS Tahoe 26 remain vulnerable. No public exploits have been reported yet, but the potential for exploitation exists given the severity of the sandbox escape. This vulnerability could be leveraged by malicious apps or attackers who trick users into running them, enabling them to execute arbitrary code with escalated privileges and potentially compromise the entire system.

For European organizations, this vulnerability poses a significant threat, particularly those that rely on macOS devices for critical operations, including government agencies, financial institutions, and technology firms. A successful sandbox escape can lead to full system compromise, allowing attackers to access sensitive data, install persistent malware, or disrupt services. The confidentiality of corporate and personal data could be severely impacted, along with the integrity of system processes and availability of services. Since the exploit requires local access and user interaction, phishing or social engineering attacks could be vectors to trigger the vulnerability. The risk is heightened in environments where macOS is widely used or where endpoint security controls are lax. Additionally, organizations with Bring Your Own Device (BYOD) policies that include macOS devices may face increased exposure. The absence of known exploits in the wild provides a window for proactive mitigation, but the high severity score underscores the urgency of patching.

European organizations should prioritize upgrading all macOS devices to macOS Tahoe 26 or later, where the vulnerable code has been removed. Until full deployment is achieved, implement strict application whitelisting to prevent untrusted or unknown applications from executing. Employ endpoint detection and response (EDR) solutions capable of monitoring for suspicious sandbox escape behaviors. Educate users about the risks of running unverified applications and the importance of avoiding suspicious links or downloads that could trigger user interaction-based exploits. Restrict local access to macOS systems by enforcing strong physical and logical access controls. Regularly audit installed applications and remove unnecessary or potentially risky software. Additionally, monitor for unusual system activity that could indicate exploitation attempts. Organizations should also review and update their incident response plans to include scenarios involving sandbox escape attacks on macOS devices.