Mattermost versions 10.1.x <= 10.1.2, 10.0.x <= 10.0.2, 9.11.x <= 9.11.4, 9.5.x <= 9.5.12 fail to limit the file size for slack import file uploads which allows a user to cause a DoS via zip bomb by importing data in a team they are a team admin.
Mattermost versions 10.1.x <= 10.1.2, 10.0.x <= 10.0.2, 9.11.x <= 9.11.4, and 9.5.x <= 9.5.12 fail to prevent concurrently checking and updating the failed login attempts. which allows an attacker to bypass of "Max failed attempts" restriction and send a big number of login attempts before being blocked via simultaneously sending multiple login requests
Mattermost versions 9.7.x <= 9.7.5, 9.8.x <= 9.8.2 and 9.9.x <= 9.9.2 fail to properly propagate permission scheme updates across cluster nodes which allows a user to keep old permissions, even if the permission scheme has been updated.
Mattermost versions 10.0.x <= 10.0.0 and 9.11.x <= 9.11.2 fail to properly query ElasticSearch when searching for the channel name in channel switcher which allows an attacker to get private channels names of channels that they are not a member of, when Elasticsearch v8 was enabled.
Mattermost versions 9.11.x <= 9.11.2, and 9.5.x <= 9.5.10 fail to protect the mfa code against replay attacks, which allows an attacker to reuse the MFA code within ~30 seconds
Mattermost versions 9.10.x <= 9.10.2, 9.11.x <= 9.11.1, 9.5.x <= 9.5.9 and 10.0.x <= 10.0.0 fail to properly authorize the requests to /api/v4/channels which allows a User or System Manager, with "Read Groups" permission but with no access for channels to retrieve details about private channels that they were not a member of by sending a request to /api/v4/channels.
Mattermost versions 9.10.x <= 9.10.2, 9.11.x <= 9.11.1, 9.5.x <= 9.5.9 fail to sanitize user inputs in the frontend that are used for redirection which allows for a one-click client-side path traversal that is leading to CSRF in Playbooks
Mattermost versions 9.10.x <= 9.10.2, 9.11.x <= 9.11.1 and 9.5.x <= 9.5.9 fail to prevent detailed error messages from being displayed in Playbooks which allows an attacker to generate a large response and cause an amplified GraphQL response which in turn could cause the application to crash by sending a specially crafted request to Playbooks.
Mattermost versions 9.10.x <= 9.10.2, 9.11.x <= 9.11.1, 9.5.x <= 9.5.9 fail to check that the origin of the message in an integration action matches with the original post metadata which allows an authenticated user to delete an arbitrary post.