CVE-2023-42935 in macOS
Summary
by MITRE • 01/23/2024
An authentication issue was addressed with improved state management. This issue is fixed in macOS Ventura 13.6.4. A local attacker may be able to view the previous logged in user’s desktop from the fast user switching screen.
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Analysis
by VulDB Data Team • 06/21/2025
The vulnerability identified as CVE-2023-42935 represents a significant authentication flaw in macOS Ventura 13.6.4 that affects the fast user switching functionality. This issue stems from inadequate state management during user session transitions, creating a persistent security gap that allows unauthorized access to previously logged-in user sessions. The flaw specifically manifests when users attempt to switch between accounts using the fast user switching screen, where the system fails to properly clear or secure the display of the previous user's desktop environment.
This authentication weakness operates at the session management layer of the operating system, where proper state transitions should ensure that all visual and interactive elements from the previous user's session are completely cleared from the display before presenting the login interface. The vulnerability enables a local attacker to potentially observe sensitive information, applications, and desktop contents from the previous user's session, creating an information disclosure risk that could expose personal data, confidential documents, or system interactions. The issue falls under the category of improper access control as defined by CWE-284, specifically relating to inadequate session management and state handling.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a potential vector for social engineering attacks and credential theft. An attacker positioned near an affected system could observe the previous user's activities, potentially capturing sensitive information such as passwords, personal communications, or business-critical data. This risk is particularly concerning in shared office environments or public computing spaces where multiple users access the same system. The vulnerability affects the fundamental security principle of user isolation, where each user session should remain completely separate and secure from other active sessions. The issue demonstrates a failure in the system's implementation of the principle of least privilege, as it allows unauthorized access to another user's session without proper authentication.
Mitigation strategies for this vulnerability center around applying the official security update that addresses the state management issue in macOS Ventura 13.6.4. System administrators should ensure all affected systems receive the patch immediately to prevent exploitation. Additionally, organizations should implement additional security controls such as configuring automatic screen locking after periods of inactivity, disabling fast user switching where possible, and establishing clear policies for secure computing environments. The vulnerability highlights the importance of proper session management and state handling in operating systems, aligning with ATT&CK technique T1548.001 for privilege escalation through session management weaknesses. Organizations should also consider implementing monitoring solutions to detect unauthorized access attempts or suspicious user switching patterns that could indicate exploitation of this vulnerability.