Apple Patches Critical macOS Screen Sharing Authentication Flaw

Apple Inc. released emergency security updates on August 6 and 7, 2026, to patch a critical vulnerability in the macOS Screen Sharing feature. The flaw, tracked as CVE-2026-65400, could allow an attacker on the same network to authenticate to Screen Sharing without valid credentials. This would potentially grant unauthorized access to a Mac's display and control, enabling attackers to view personal files, launch applications, or install malware.

Apple addressed the issue through improved state management and issued the fix across three operating system versions: macOS Tahoe 26.6.1, macOS Sequoia 15.7.9, and macOS Sonoma 14.8.9. The company credited the discovery of the authentication flaw to the security research group Bynario Atlas.

This update follows a previous release on July 27, 2026, which addressed three other distinct Screen Sharing Server vulnerabilities involving network interception, denial-of-service, and sensitive data access. While Apple did not report that the latest vulnerability had been publicly disclosed or actively exploited prior to the release, the company deployed the patches across three generations of macOS due to the severity of the risk.