Resource Exhaustion in Mattermost Server versions 8.1.x before 8.1.10 fails to limit the size of the payload that can be read and parsed allowing an attacker to send a very large email payload and crash the server.

Uncontrolled Resource Consumption in Mattermost Mobile versions before 2.13.0 fails to limit the size of the code block that will be processed by the syntax highlighter, allowing an attacker to send a very large code block and crash the mobile app.

Mattermost versions 8.1.x before 8.1.9, 9.2.x before 9.2.5, 9.3.0, and 9.4.x before 9.4.2 fail to limit the number of role names requested from the API, allowing an authenticated attacker to cause the server to run out of memory and crash by issuing an unusually large HTTP request.

Mattermost version 8.1.x before 8.1.9 fails to sanitize data associated with permalinks when a plugin updates an ephemeral post, allowing an authenticated attacker who can control the ephemeral post update to access individual posts' contents in channels they are not a member of.

A race condition in Mattermost versions 8.1.x before 8.1.9, and 9.4.x before 9.4.2 allows an authenticated attacker to gain unauthorized access to individual posts' contents via carefully timed post creation while another user deletes posts.

Mattermost versions 8.1.x before 8.1.9, 9.2.x before 9.2.5, and 9.3.0 fail to sanitize the metadata on posts containing permalinks under specific conditions, which allows an authenticated attacker to access the contents of individual posts in channels they are not a member of.

Mattermost fails to check the "invite_guest" permission when inviting guests of other teams to a team, allowing a member with permissions to add other members but not to add guests to add a guest to a team as long as the guest was already a guest in another team of the server

Mattermost fails to properly validate the length of the emoji value in the custom user status, allowing an attacker to send multiple times a very long string as an emoji value causing high resource consumption and possibly crashing the server.

Mattermost fails to properly authorize the requests fetching team associated AD/LDAP groups, allowing a user to fetch details of AD/LDAP groups of a team that they are not a member of. 

Mattermost fails to properly restrict the access of files attached to posts in an archived channel, resulting in members being able to access files of archived channels even if the “Allow users to view archived channels” option is disabled.