Bottom line: CVE-2026-65400 allows authentication-free access to macOS devices via Screen Sharing and is already being actively exploited.
An authentication flaw in the macOS Screen Sharing feature allows attackers to establish a connection to remote devices without valid credentials. The vulnerability CVE-2026-65400 is already being actively exploited.
The vulnerability affects the Screen Sharing feature of macOS and allows attackers to connect to a remote device without valid credentials. The underlying flaw lies in the feature’s authentication mechanism. The vulnerability is tracked under the identifier CVE-2026-65400.
Since Screen Sharing is frequently enabled on macOS systems for remote support and remote maintenance, the flaw opens a direct access path for attackers to devices on the corporate network without the need to compromise credentials. Combined with lateral movement within a network, this can be used to reach additional systems, increasing the risk beyond the individual affected machine.
The active exploitation of the vulnerability in the wild increases the urgency for organizations to apply the provided patch promptly. CISOs should check which macOS devices have Screen Sharing enabled, prioritize tracking patch status, and, where an update cannot be applied immediately, temporarily disable the feature or restrict access via network segmentation and firewall rules.
Source: www.security-insider.de · Published August 20, 2026
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