Videoconferencing platform Zoom recently published an urgent security advisory to resolve critical vulnerabilities that could allow malicious attackers to gain complete remote control over user devices during active video calls. Discovered by cybersecurity researchers at A Security, the severe flaw was dubbed “Zoomsday,” highlighting major risks associated with real-time collaboration features in modern communication software. The Zoomsday vulnerability was particularly dangerous due to its zero-click execution mechanism, operating seamlessly without requiring any direct interaction from the targeted victim or displaying any visual indicators. From a technical standpoint, the vulnerabilities were located within the protocol responsible for managing real-time annotations during screen-sharing sessions. The scope of the issue was comprehensive, affecting all major supported operating systems, including Windows, macOS, Linux, iOS, and Android.