Attention, unwanted window sharing: A bug in screen sharing in macOS 14.2 Sonoma can cause Mac users to involuntarily share hidden windows with others without being able to see it directly themselves. At best, this leads to amusement among video conference participants, but it can just as quickly have unpleasant consequences, depending on which window contents are unintentionally and unnoticed revealed to the public.
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Window disclosure in Zoom, Slack, FaceTime & Co
The error occurs when multiple spaces or desks are used, for example to separate professional and personal activities. If the user in macOS 14.2 shares the currently active screen in a Zoom call, for example, they may also share windows from the invisible spaces. Only the other participants in the video conference can see this content that is open in other spaces – the person sharing the screen does not notice this directly.
Actually, other video conference participants should only see the almost empty desktop here – but macOS also shares open windows from other spaces, as can only be seen in the small control menu.
The Mac & i editorial team was able to reproduce the bug in video calls with screen sharing in Zoom, Slack and Apple FaceTime. Other video conferencing tools are probably also affected. The error did not occur for us in Microsoft Teams (new like “Classic”).
The unwanted window release usually happened when you perform certain window actions, such as minimizing open windows in the dock or displaying the desktop. In this case, the person sharing the screen only sees their background image as expected, but all video conference participants also see the windows hidden in other spaces. The user can only discover the unwanted disclosure of content if they click on the screen sharing button in the menu bar, which is new in Sonoma, and view the small preview.
Bug reported to Apple
Developer Craig Hockenberry wrote that he reported the bug to Apple about a month ago, drawing attention to the problem on Mastodon. So far there has been no response. From Apple’s security team he just received the answer“No security issue could be identified” in the bug report.
macOS 14.2 Sonoma has only been available for a few days. Mac users who use screen sharing intensively should currently pay close attention to what other content they have open. If you only split individual windows instead of the entire screen, the bug doesn’t seem to occur.
(lb)