FlagThis — Daily Cybersecurity Intelligence Briefing

CVE-2026-65400 is a high-severity state management vulnerability within the macOS screen sharing capability affecting macOS Tahoe, Sequoia, and Sonoma. Attackers targeting exposed Port 5900 can bypass authentication to gain immediate root-level access, enabling full remote takeover of the user interface, including screen visibility and input manipulation. The Netherlands National Cyber Security Centrum (NCSC) has confirmed active exploitation in the wild, primarily utilizing the flaw to deploy Monero cryptominers for resource theft. Immediate remediation requires updating to the latest macOS versions and implementing network restrictions to prevent direct internet exposure of VNC services.