CVE-2025-24036 is a vulnerability identified in Microsoft AutoUpdate (MAU) for Mac, specifically version 4.0.0. The flaw is a Time-of-check Time-of-use (TOCTOU) race condition, classified under CWE-367, which occurs when the system checks a condition and then uses the result of that check without ensuring the state remains unchanged. This race condition can be exploited by an attacker with limited privileges on the local machine to elevate their privileges, potentially gaining administrative or root-level access. The vulnerability impacts the update mechanism of MAU, which is responsible for applying patches and updates to Microsoft software on Mac devices. The CVSS v3.1 base score of 7.0 reflects a high severity, with an attack vector limited to local access (AV:L), requiring high attack complexity (AC:H), and low privileges (PR:L). No user interaction is needed (UI:N), and the scope remains unchanged (S:U). The impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H), indicating that successful exploitation could lead to full system compromise. Although no known exploits are reported in the wild, the vulnerability's nature and affected component make it a critical concern for organizations relying on Microsoft software updates on Mac platforms. The lack of available patches at the time of publication necessitates immediate attention to mitigate potential exploitation risks.

The vulnerability allows an attacker with local access and limited privileges to escalate their privileges to a higher level, potentially administrative or root. This can lead to unauthorized code execution, complete system compromise, and the ability to manipulate or disable security controls. The impact extends to confidentiality, as sensitive data could be accessed or exfiltrated; integrity, as system files and configurations could be altered; and availability, as attackers could disrupt or disable critical services. Organizations relying on Microsoft AutoUpdate for Mac are at risk of targeted attacks, especially in environments where multiple users share devices or where endpoint security is less stringent. The high complexity of exploitation and requirement for local access limit widespread automated attacks but do not eliminate the risk of targeted intrusions, insider threats, or malware leveraging this vulnerability post-initial compromise. The absence of known exploits in the wild currently reduces immediate risk but underscores the importance of proactive mitigation.

Until an official patch is released, organizations should implement strict local access controls to limit the number of users with any privileges on Mac systems running Microsoft AutoUpdate. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious activities related to the update process. Regularly audit and restrict file system permissions around update binaries and temporary directories to prevent race condition exploitation. Consider disabling automatic updates temporarily if operationally feasible and replace with manual update processes controlled by trusted administrators. Educate users about the risks of executing untrusted code and monitor logs for unusual privilege escalation attempts. Once Microsoft releases a patch, prioritize immediate deployment across all affected systems. Additionally, maintain up-to-date backups and incident response plans to quickly recover from potential compromises.