CVE-2026-6689

Summary

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

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost11.6.0 <= 11.6.1affected
MattermostMattermost11.5.0 <= 11.5.4affected
MattermostMattermost10.11.0 <= 10.11.15affected
MattermostMattermost10.11.0 <= 10.11.16affected
MattermostMattermost11.7.0unaffected
MattermostMattermost11.6.2unaffected
MattermostMattermost11.5.5unaffected
MattermostMattermost10.11.16unaffected
MattermostMattermost10.11.17unaffected

Weaknesses

  • CWE-862: CWE-862: Missing Authorization

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References