A newly disclosed security flaw in Zoom raised fresh concerns about the risks hidden inside everyday video-conferencing features. Dubbed ‘Zoomsday,’ the vulnerability could allow a malicious participant in a Zoom meeting to remotely execute code on another participant’s device without requiring the victim to click a link or download a file.
The issue is particularly concerning since it was linked to Zoom’s screen-sharing annotation feature, which allowed meeting participants to draw, highlight, or add text while another user was sharing their screen.
The vulnerability, tracked as CVE-2026-53413, affected Zoom's annotation protocol. Researchers from cybersecurity firm A Security found that a specially crafted annotation message could be used to trigger malicious code on another participant's device.
In a potential attack, a participant would not necessarily need to persuade the target into opening an attachment or approving an unfamiliar request. The flaw could instead be exploited through the meeting itself, making the attack particularly difficult for an ordinary user to detect.
Researchers said the vulnerability could potentially allow attackers to gain control of affected devices, access files or install malicious software. The flaw was reported across Zoom's supported platforms, including Windows, macOS, Linux, Android and iOS.
Screen sharing is generally viewed as a routine collaboration feature. Employees use it for presentations, remote support, training sessions and business meetings. The Zoomsday incident showed that features designed for interaction can also create additional security entry points.
The problem was not simply that users were sharing their screens. The vulnerability involved the communication process behind Zoom's annotation system. That meant even a feature that appears harmless during a meeting could become a security risk if its underlying software contains a serious flaw.
The discovery also attracted attention since researchers said publicly available AI models helped them investigate and develop an exploit for the vulnerability in less than a day, using fewer than 20 prompts.
That development has broader implications for cybersecurity. AI tools can help security teams analyse code and identify weaknesses, but the same capabilities can also lower the technical barrier for attackers.
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Zoom released security updates addressing the vulnerability and other recently disclosed security issues. The company urged users to keep their Zoom applications updated. For businesses that rely heavily on video meetings, the incident is a reminder that security cannot stop at passwords and meeting links. Software updates, controlled screen-sharing permissions and careful participant management remain important safeguards.
The Zoomsday episode highlights a wider cybersecurity challenge: as collaboration platforms become more feature-rich, even familiar tools such as annotations and screen sharing need continuous security testing.