CVE-2025-24255 is a vulnerability in Apple macOS that allows an application to escape its sandbox environment due to a file access issue caused by inadequate input validation (CWE-20). The sandbox is a critical security mechanism designed to isolate applications and restrict their access to system resources and user data. This vulnerability undermines that isolation, enabling a malicious or compromised app to access files and resources beyond its intended scope. The issue affects multiple macOS versions prior to Ventura 13.7.5, Sequoia 15.4, and Sonoma 14.7.5, where Apple has implemented improved input validation to address the flaw. The CVSS 3.1 vector indicates the attack requires local access (AV:L), has low complexity (AC:L), requires no privileges (PR:N), and no user interaction (UI:N). The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H), meaning an attacker can fully compromise the system's security properties. Although no public exploits have been reported, the vulnerability's characteristics make it a critical concern for environments relying on macOS sandboxing for security containment. Organizations should be aware that any app, including those downloaded from the App Store or sideloaded, could exploit this flaw if unpatched.

For European organizations, this vulnerability poses a significant risk, especially those with macOS endpoints in use for sensitive operations, development, or critical infrastructure management. The ability for an app to break out of its sandbox can lead to unauthorized access to sensitive files, credential theft, installation of persistent malware, and potential lateral movement within networks. Confidentiality breaches could expose personal data protected under GDPR, leading to regulatory penalties and reputational damage. Integrity and availability impacts could disrupt business operations and critical services. The risk is heightened in sectors such as finance, healthcare, government, and technology, where macOS devices are commonly used and data sensitivity is high. Given the ease of exploitation without user interaction or privileges, attackers with local access—such as insiders or those who have compromised a lower-privileged account—can escalate their control significantly. The lack of known exploits in the wild provides a window for proactive patching and mitigation before widespread attacks occur.

European organizations should immediately verify their macOS versions and deploy the security updates macOS Ventura 13.7.5, Sequoia 15.4, or Sonoma 14.7.5 as applicable. Beyond patching, organizations should enforce strict application control policies to limit installation of untrusted or unnecessary apps, reducing the attack surface. Employ endpoint detection and response (EDR) solutions capable of monitoring for anomalous file access patterns and sandbox escape attempts. Implement least privilege principles for user accounts to minimize the impact of local exploits. Regularly audit installed applications and remove or restrict those not essential to business operations. Network segmentation can help contain potential lateral movement from compromised macOS devices. Additionally, educate users about the risks of installing unverified software and maintain robust logging to facilitate incident investigation. Finally, integrate macOS-specific threat intelligence feeds to stay informed of emerging exploitation techniques related to this vulnerability.