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.
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
| 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) |
Access control involves the use of several protection mechanisms such as:
When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses: