CVE-2025-31259 is a vulnerability in Apple macOS identified as a privilege escalation flaw stemming from inadequate input sanitization (CWE-20). This vulnerability allows a local application with low privileges to gain elevated privileges without requiring user interaction. The issue was addressed in macOS Sequoia 15.5 through improved input validation mechanisms. The CVSS 3.1 base score is 7.8, indicating high severity, with attack vector local (AV:L), low attack complexity (AC:L), low privileges required (PR:L), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). Exploiting this vulnerability could enable an attacker to execute arbitrary code or commands with elevated privileges, potentially compromising the entire system. Although no known exploits are currently reported in the wild, the vulnerability presents a significant risk due to its potential impact and ease of exploitation. The lack of specified affected versions suggests that multiple macOS versions prior to 15.5 may be vulnerable. This vulnerability is particularly concerning for environments where local access controls are weak or where untrusted applications can be executed. The fix involves enhanced input sanitization to prevent malicious input from triggering privilege escalation.

The vulnerability allows an attacker with local access and low privileges to escalate their privileges to a higher level, potentially root or system-level. This can lead to full system compromise, including unauthorized access to sensitive data, modification or deletion of critical files, installation of persistent malware, and disruption of system availability. Organizations relying on macOS for critical operations, development, or sensitive data processing face significant risks if systems remain unpatched. The flaw undermines the security boundary between user-level and privileged processes, increasing the attack surface for insider threats or malware that gains initial foothold with limited privileges. The absence of required user interaction simplifies exploitation scenarios, making automated or stealthy attacks more feasible. Although no active exploits are known, the vulnerability's characteristics suggest it could be leveraged in targeted attacks or by advanced persistent threat actors. The impact extends to confidentiality, integrity, and availability, making it a comprehensive threat to affected systems.

1. Immediately update all macOS systems to version Sequoia 15.5 or later, where the vulnerability is patched. 2. Restrict local access to macOS systems to trusted users only, minimizing the risk of unprivileged code execution. 3. Implement application whitelisting and endpoint protection solutions that can detect or block suspicious privilege escalation attempts. 4. Monitor system logs and audit privilege escalation events to detect potential exploitation attempts early. 5. Employ least privilege principles for user accounts and services to limit the impact of any successful exploitation. 6. Conduct regular security assessments and penetration testing focusing on privilege escalation vectors. 7. Educate users and administrators about the risks of running untrusted applications locally. 8. Use macOS security features such as System Integrity Protection (SIP) and secure boot to reduce the attack surface. 9. Maintain up-to-date backups to enable recovery in case of compromise. 10. Stay informed about any emerging exploits or additional patches related to this vulnerability.