CVE-2025-55317 is a vulnerability classified under CWE-59 (Improper Link Resolution Before File Access) found in Microsoft AutoUpdate (MAU) for Mac, specifically version 4.0.0. The issue arises from the software's improper handling of symbolic links or other file system links before accessing files during the update process. An authorized local attacker can exploit this flaw by creating or manipulating symbolic links to redirect file operations to unintended locations, thereby escalating their privileges on the system. This elevation of privilege can allow the attacker to gain higher-level access than originally permitted, potentially leading to full system compromise. The vulnerability does not require user interaction but does require the attacker to have some level of local access (low privileges). The CVSS v3.1 score of 7.8 reflects high severity, with impacts on confidentiality, integrity, and availability, and low attack complexity. No public exploits are known at this time, but the vulnerability's nature makes it a critical concern for environments relying on Microsoft AutoUpdate for Mac. The lack of available patches at the time of publication means organizations must rely on interim mitigations until updates are released.

For European organizations, this vulnerability poses a significant risk especially in environments where Mac devices are prevalent and Microsoft AutoUpdate is used to manage software updates. Exploitation could lead to unauthorized privilege escalation, allowing attackers to execute arbitrary code with elevated rights, access sensitive data, modify system files, or disrupt availability. This can compromise the integrity of critical business applications and data, potentially leading to data breaches, operational downtime, and regulatory non-compliance under GDPR. The threat is particularly relevant for sectors with high Mac adoption such as creative industries, education, and certain government agencies. The local access requirement limits remote exploitation but insider threats or attackers who gain initial foothold on endpoints can leverage this vulnerability to deepen their access. The absence of known exploits currently reduces immediate risk but organizations should act proactively given the high severity and potential impact.

1. Restrict local user permissions rigorously to minimize the number of users with access to Mac devices and limit their ability to create or manipulate symbolic links. 2. Implement application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious file system activities related to symbolic link creation or modification. 3. Enforce strict access controls on update mechanisms and related directories to prevent unauthorized file manipulations. 4. Monitor system logs for unusual behavior indicative of privilege escalation attempts. 5. Educate users about the risks of local privilege escalation and enforce policies to prevent unauthorized software installations or modifications. 6. Prepare to deploy patches immediately once Microsoft releases updates addressing this vulnerability. 7. Consider isolating critical Mac systems or using virtualization to contain potential exploitation. 8. Regularly audit and review local accounts and permissions to reduce attack surface.