CPE
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file ownership and access control, allowing an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.