Mattermost allows authenticated guest users to enumerate user IDs outside their allowed visibility scope

Mattermost versions 11.2.x = 11.2.2, 10.11.x = 10.11.10, 11.4.x = 11.4.0, 11.3.x = 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint...