Mattermost Desktop App versions <=5.8.0 fail to safeguard screen capture functionality which allows an attacker to silently capture high-quality screenshots via JavaScript APIs.

Mattermost Mobile Apps versions <=2.18.0 fail to disable autocomplete during login while typing the password and visible password is selected, which allows the password to get saved in the dictionary when the user has Swiftkey as the default keyboard, the masking is off and the password contains a special character..

Mattermost Desktop App versions <=5.8.0 fail to specify an absolute path when searching the cmd.exe file, which allows a local attacker who is able to put an cmd.exe file in the Downloads folder of a user's machine to cause remote code execution on that machine.

Mattermost Plugin Channel Export versions <=1.0.0 fail to restrict concurrent runs of the /export command which allows a user to consume excessive resource by running the /export command multiple times at once.

Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.0, 9.8.x <= 9.8.2 fail to enforce permissions which allows a guest user with read access to upload files to a channel.

Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.x <= 9.10.0, 9.8.x <= 9.8.2 fail to properly enforce permissions which allows a user with systems manager role with read-only access to teams to perform write operations on teams.

Mattermost versions 9.5.x <= 9.5.7, 9.10.x <= 9.10.0 fail to properly enforce permissions which allows a team admin user without "Add Team Members" permission to disable the invite URL.

Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.x <= 9.10.0 and 9.8.x <= 9.8.2 fail to restrict which roles can promote a user as system admin which allows a System Role with edit access to the permissions section of system console to update their role (e.g. member) to include the `manage_system` permission, effectively becoming a System Admin.

Mattermost versions 9.5.x <= 9.5.7, 9.10.x <= 9.10.0 fail to enforce proper access controls which allows any authenticated user, including guests, to mark any channel inside any team as read for any user.

Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.x <= 9.10.0, 9.8.x <= 9.8.2 fail to restrict the input in POST /api/v4/users which allows a user to manipulate the creation date in POST /api/v4/users tricking the admin into believing their account is much older.