CVE-2025-31259 is a high-severity vulnerability affecting Apple macOS, specifically addressed in macOS Sequoia 15.5. The vulnerability arises from insufficient input sanitization, categorized under CWE-20 (Improper Input Validation). This flaw allows a malicious application with limited privileges (low privileges) to potentially escalate its privileges without requiring user interaction. The CVSS 3.1 base score is 7.8, indicating a high impact with the vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. This means the attack requires local access (local attack vector), low attack complexity, and privileges already present but low-level, no user interaction, and the scope remains unchanged. The impact on confidentiality, integrity, and availability is high, meaning an attacker could fully compromise the system, access sensitive data, modify system files, or disrupt system availability. The vulnerability was mitigated by Apple through improved input sanitization in the affected component, preventing malicious inputs from triggering the privilege escalation. No known exploits are reported in the wild as of the publication date, but the potential for exploitation remains significant due to the nature of the flaw and the high impact score.

For European organizations, this vulnerability poses a significant risk, especially for those relying on macOS systems in their IT environments, including enterprises, creative industries, and governmental bodies. An attacker exploiting this vulnerability could gain elevated privileges on affected macOS devices, leading to unauthorized access to sensitive corporate or personal data, disruption of critical services, or deployment of further malware with system-level control. This could result in data breaches, intellectual property theft, operational downtime, and reputational damage. Given the high confidentiality, integrity, and availability impacts, organizations with macOS endpoints must prioritize remediation to prevent lateral movement and privilege escalation within their networks. The lack of required user interaction increases the risk of silent compromise, making detection and response more challenging.

European organizations should immediately verify their macOS versions and prioritize upgrading to macOS Sequoia 15.5 or later, where the vulnerability is patched. Since the vulnerability requires local access, organizations should enforce strict endpoint security policies, including limiting physical and remote access to macOS devices. Implement application whitelisting and restrict installation of untrusted or unsigned applications to reduce the risk of malicious apps exploiting this flaw. Employ endpoint detection and response (EDR) solutions capable of monitoring for unusual privilege escalation attempts. Regularly audit user privileges and remove unnecessary administrative rights. Additionally, organizations should conduct security awareness training to reinforce the importance of device security and vigilance against suspicious activity. Network segmentation can help contain potential compromises. Finally, maintain up-to-date backups and incident response plans tailored for macOS environments to ensure rapid recovery if exploitation occurs.