CVE-2026-3115
published 2026-03-26CVE-2026-3115: Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs…
medium4.3CVSS 3.1
AVNACLPRLUINSUCLINAN
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594
Affected
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | mattermost_mattermost_server_v8 | >= 10.11.0-rc1 < 10.11.11 | 10.11.11 |
| github.com | mattermost_mattermost_server_v8 | >= 11.2.0-rc1 < 11.2.3 | 11.2.3 |
| github.com | mattermost_mattermost_server_v8 | >= 11.3.0-rc1 < 11.3.2 | 11.3.2 |
| github.com | mattermost_mattermost_server_v8 | >= 11.4.0 < 11.4.1 | 11.4.1 |
| github.com | mattermost_mattermost_server_v8 | >= 8.0.0-20260105080200-d27a2195068d < 8.0.0-20260217110922-b7d4a1f1f59b | 8.0.0-20260217110922-b7d4a1f1f59b |
| mattermost | mattermost | 10.11.0 – 10.11.10 | — |
| mattermost | mattermost | 11.2.0 – 11.2.2 | — |
| mattermost | mattermost | 11.3.0 – 11.3.1 | — |
| mattermost | mattermost | 11.4.0 – 11.4.0 | — |
| mattermost | mattermost_server | — | — |
| mattermost | mattermost_server | >= 10.11.0 < 10.11.11 | 10.11.11 |
| mattermost | mattermost_server | >= 11.2.0 < 11.2.3 | 11.2.3 |
| mattermost | mattermost_server | >= 11.3.0 < 11.3.2 | 11.3.2 |