CVE-2025-31244 is a high-severity vulnerability affecting Apple macOS, specifically related to a file quarantine bypass that could allow an application to break out of its sandbox environment. The sandbox is a critical security mechanism in macOS designed to isolate applications and restrict their access to system resources and user data, thereby limiting the potential damage from malicious or compromised apps. This vulnerability arises from insufficient checks in the file quarantine mechanism, which is intended to prevent untrusted or downloaded files from executing without proper scrutiny. By bypassing this quarantine, a malicious app could escape the sandbox restrictions, gaining elevated privileges and broader access to the system than intended. The CVSS v3.1 base score of 8.8 reflects the high impact on confidentiality, integrity, and availability, with the vector indicating that the attack requires local access (AV:L), low attack complexity (AC:L), low privileges (PR:L), no user interaction (UI:N), and that the scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The vulnerability is fixed in macOS Sequoia 15.5 with additional checks in the file quarantine process. No known exploits are currently reported in the wild, but the potential for exploitation is significant given the ability to break out of sandbox constraints, which could lead to full system compromise or unauthorized data access.

For European organizations, this vulnerability poses a serious risk, especially for enterprises and institutions that rely on macOS devices for sensitive operations, including government agencies, financial institutions, and technology companies. A successful exploit could allow attackers to bypass sandbox restrictions, leading to unauthorized access to confidential data, installation of persistent malware, or disruption of critical services. The lack of required user interaction and the low privilege needed to exploit the vulnerability increase the risk of automated or stealthy attacks within corporate environments. This could undermine trust in macOS security, potentially leading to data breaches, intellectual property theft, and operational downtime. Organizations with remote or hybrid workforces using macOS devices are particularly vulnerable, as attackers could leverage local access through compromised user devices to escalate privileges and move laterally within networks.

European organizations should prioritize updating all macOS devices to version Sequoia 15.5 or later as soon as it becomes available to ensure the vulnerability is patched. Beyond patching, organizations should implement strict application control policies using Apple’s built-in tools such as Gatekeeper and System Integrity Protection (SIP) to limit the execution of untrusted applications. Employ endpoint detection and response (EDR) solutions capable of monitoring for unusual sandbox escape behaviors and privilege escalations. Regularly audit and restrict local user privileges to minimize the risk of low-privilege exploitation. Additionally, enforce network segmentation to contain potential lateral movement from compromised macOS endpoints. Security awareness training should emphasize the risks of running unverified applications, even within sandboxed environments. Finally, maintain up-to-date backups and incident response plans tailored for macOS environments to quickly recover from potential exploitation.