Zoom for Windows clients before version 5.13.3, Zoom Rooms for Windows clients before version 5.13.5 and Zoom VDI for Windows clients before 5.13.1 contain an information disclosure vulnerability. A recent update to the Microsoft Edge WebView2 runtime used by the affected Zoom clients, transmitted text to Microsoft’s online Spellcheck service instead of the local Windows Spellcheck. Updating Zoom remediates this vulnerability by disabling the feature. Updating Microsoft Edge WebView2 Runtime to at least version 109.0.1481.0 and restarting Zoom remediates this vulnerability by updating Microsoft’s telemetry behavior.
Zoom clients before version 5.13.5 contain a STUN parsing vulnerability. A malicious actor could send specially crafted UDP traffic to a victim Zoom client to remotely cause the client to crash, causing a denial of service.
The Zoom Client for Meetings (for Android, iOS, Linux, macOS, and Windows) before version 5.11.0 are susceptible to a URL parsing vulnerability. If a malicious Zoom meeting URL is opened, the malicious link may direct the user to connect to an arbitrary network address, leading to additional attacks including the potential for remote code execution through launching executables from arbitrary paths.
Zoom through 5.5.4 sometimes allows attackers to read private information on a participant's screen, even though the participant never attempted to share the private part of their screen. When a user shares a specific application window via the Share Screen functionality, other meeting participants can briefly see contents of other application windows that were explicitly not shared. The contents of these other windows can (for instance) be seen for a short period of time when they overlay the shared window and get into focus. (An attacker can, of course, use a separate screen-recorder application, unsupported by Zoom, to save all such contents for later replays and analysis.) Depending on the unintentionally shared data, this short exposure of screen contents may be a more or less severe security issue.
Zoom clients on Windows (before version 4.1.34814.1119), Mac OS (before version 4.1.34801.1116), and Linux (2.4.129780.0915 and below) are vulnerable to unauthorized message processing. A remote unauthenticated attacker can spoof UDP messages from a meeting attendee or Zoom server in order to invoke functionality in the target client. This allows the attacker to remove attendees from meetings, spoof messages from users, or hijack shared screens.