Description
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel member-management permission during playbook run creation, allowing an authenticated channel member to add an arbitrary user to a restricted channel via the run owner field.. Mattermost Advisory ID: MMSA-2026-00677
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mattermost | Mattermost | 11.9.0 – ≤ 11.9.0, 11.8.0 – ≤ 11.8.4, 11.7.0 – ≤ 11.7.7, 10.11.0 – ≤ 10.11.22 | 11.10.0 |
References
- MMSA-2026-00677 vendor-advisory