Mattermost versions 9.5.x <= 9.5.5 and 9.8.0 fail to properly sanitize the recipients of a webhook event which allows an attacker monitoring webhook events to retrieve the channel IDs of archived or restored channels.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Mattermost | Mattermost | 9.5.0 (including) | 9.5.6 (excluding) |
| Mattermost | Mattermost | 9.8.0 (including) | 9.8.1 (excluding) |