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.
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Mattermost_server | Mattermost | 8.1.0 (including) | 8.1.9 (excluding) |
| Mattermost_server | Mattermost | 9.2.0 (including) | 9.2.5 (excluding) |
| Mattermost_server | Mattermost | 9.3.0 (including) | 9.3.0 (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: