CVE-2026-6689Medium· 4.3▾ SunlitMattermost doesn't enforce PermissionInviteUser when setting AllowOpenInvite or AllowedDomains during team creation
▾ Sunlit zone — Low / medium · no exploitation signal
impact 23.7 · likelihood 0 · exploitation 0
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Exploit-prediction probability, daily snapshots since Aug 25.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
0.2%
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
github.com/mattermost/mattermost-server >= 11.6.0, < 11.6.1github.com/mattermost/mattermost-server >= 11.5.0, < 11.5.5github.com/mattermost/mattermost-server >= 10.11.0, < 10.11.17github.com/mattermost/mattermost/server/v8 >= 8.0.0-20250731163400-5b955468ea1e, < 8.0.0-20260501144115-7d6816abdfd1Upgrade to a patched release:
github.com/mattermost/mattermost-server 11.6.1github.com/mattermost/mattermost-server 11.5.5github.com/mattermost/mattermost-server 10.11.17github.com/mattermost/mattermost/server/v8 8.0.0-20260501144115-7d6816abdfd1Connected by shared product, vendor, weakness, or advisory.
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