Description
Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669
CVSS breakdown
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low
Affected products
- Mattermost / Mattermost11.7.0 – 11.7.0
- Mattermost / Mattermost10.11.0 – 10.11.17
- Mattermost / Mattermost11.8.0 – 11.8.0
- Mattermost / Mattermost11.7.1 – 11.7.1
- Mattermost / Mattermost10.11.18 – 10.11.18