CVE-2026-3115
Fixed in a distro release EPSS <1%CVSS 4.3
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
Products: Mattermost
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Go | github.com/mattermost/mattermost-server | 10.11.11+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.2.3+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.3.2+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.4.1+incompatible |
| Go | github.com/mattermost/mattermost-server/v5 | no fix |
| Go | github.com/mattermost/mattermost-server/v6 | no fix |
| Go | github.com/mattermost/mattermost/server/v8 | 11.4.1 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.3.2 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.2.3 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.11 |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260217110922-b7d4a1f1f59b |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| openSUSE:Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 |