Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadnt been synced before.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Mattermost_server | Mattermost | 9.5.0 (including) | 9.5.7 (excluding) |
| Mattermost_server | Mattermost | 9.7.0 (including) | 9.7.6 (excluding) |
| Mattermost_server | Mattermost | 9.8.0 (including) | 9.8.2 (excluding) |
| Mattermost_server | Mattermost | 9.9.0 (including) | 9.9.0 (including) |