Mattermost versions 9.5.x <= 9.5.5 and 9.8.0, when using shared channels with multiple remote servers connected, fail to check that the remote server A requesting the server B to update the profile picture of a user is the remote that actually has the user as a local one . This allows a malicious remote A to change the profile images of users that belong to another remote server C that is connected to the server A.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Mattermost | Mattermost | 9.5.0 (including) | 9.5.6 (excluding) |
| Mattermost | Mattermost | 9.8.0 (including) | 9.8.0 (including) |