CVE-2026-6689
Fixed in a distro release EPSS <1%CVSS 4.3
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Fail to enforce PermissionInviteUser when setting AllowOpenInvite or AllowedDomains during team creation (the check was only applied on update/patch), which allows an authenticated user holding PermissionCreateTeam but not PermissionInviteUser on the resulting team to configure invite-controlled team settings (make the team publicly joinable via open invite and/or constrain membership via allowed domains) that they are not permitted to set on an existing team via POST /api/v4/teams with allow_open_invite: true and/or a non-empty allowed_domains in the request body.. Mattermost Advisory ID: MMSA-2026-00655
Products: Mattermost
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Go | github.com/mattermost/mattermost-server | 11.6.1 |
| Go | github.com/mattermost/mattermost-server | 11.5.5 |
| Go | github.com/mattermost/mattermost-server | 10.11.17 |
| Go | github.com/mattermost/mattermost-server | 10.11.17+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.5.5+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.6.1+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 | 8.0.0-20260501144115-7d6816abdfd1 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| SUSE:Linux Enterprise Server 16.0 | govulncheck-vulndb | 0.0.20260827T195228-160000.1.1 |
| SUSE:Linux Enterprise Server for SAP applications 16.0 | govulncheck-vulndb | 0.0.20260827T195228-160000.1.1 |
| openSUSE:Leap 16.0 | govulncheck-vulndb | 0.0.20260827T195228-160000.1.1 |