Plane is an an open-source project management tool. In plane.io, a guest user doesn't have a permission to access https[:]//app[.]plane[.]so/[:]slug/settings. Prior to Plane version 1.2.0, a problem occurs when the "/api/workspaces/:slug/members/" is accessible by guest and able to list of users on a specific workspace that they joined. Since the "display_name" in the response is actually the handler of the email, a malicious guest can still identify admin users' email addresses. Version 1.2.0 fixes this issue.