---
id: CVE-2026-6689
aliases:
  - GHSA-c28q-m4gf-vg4q
title: >-
  Mattermost doesn't enforce PermissionInviteUser when setting AllowOpenInvite
  or AllowedDomains during team creation
summary: >-
  Mattermost doesn't enforce PermissionInviteUser when setting AllowOpenInvite
  or AllowedDomains during team creation
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
vendor: mattermost
product: github.com/mattermost/mattermost-server
ecosystem: go
affected:
  - 'github.com/mattermost/mattermost-server >= 11.6.0, < 11.6.1'
  - 'github.com/mattermost/mattermost-server >= 11.5.0, < 11.5.5'
  - 'github.com/mattermost/mattermost-server >= 10.11.0, < 10.11.17'
  - >-
    github.com/mattermost/mattermost/server/v8 >=
    8.0.0-20250731163400-5b955468ea1e, < 8.0.0-20260501144115-7d6816abdfd1
patched:
  - github.com/mattermost/mattermost-server 11.6.1
  - github.com/mattermost/mattermost-server 11.5.5
  - github.com/mattermost/mattermost-server 10.11.17
  - github.com/mattermost/mattermost/server/v8 8.0.0-20260501144115-7d6816abdfd1
published: '2026-06-12'
updated: '2026-08-24'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-c28q-m4gf-vg4q'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-6689'
  - url: 'https://github.com/mattermost/mattermost/pull/36402'
  - url: 'https://github.com/mattermost/mattermost/pull/36384'
  - url: 'https://github.com/mattermost/mattermost/pull/36383'
  - url: 'https://github.com/mattermost/mattermost/pull/36375'
  - url: 'https://github.com/mattermost/mattermost/pull/36188'
  - url: >-
      https://github.com/mattermost/mattermost/commit/977c791e5b54bc14fdb96a2b3dacc85da5d8c623
  - url: >-
      https://github.com/mattermost/mattermost/commit/7d6816abdfd170169f717aea43c5716a1f9ef6b0
  - url: >-
      https://github.com/mattermost/mattermost/commit/479fc42d0ec6da48e76b59608233d90bfc69769d
  - url: >-
      https://github.com/mattermost/mattermost/commit/3a96344214b1a84df70d97052d46b6f2b40b0caa
  - url: >-
      https://github.com/mattermost/mattermost/commit/2dea05864024b3254fb28c5ed679592e2b7cd672
  - url: 'https://github.com/mattermost/mattermost/releases/tag/v10.11.16'
  - url: 'https://github.com/mattermost/mattermost/releases/tag/v11.5.5'
  - url: 'https://github.com/mattermost/mattermost/releases/tag/v11.6.2'
  - url: 'https://github.com/mattermost/mattermost/releases/tag/v11.7.0'
  - url: 'https://mattermost.com/security-updates'
  - url: 'https://github.com/mattermost/mattermost'
tags:
  - osv
  - go
epss: 0.00152
epssPercentile: 0.04759
ingestedAt: '2026-08-25T19:26:23.070Z'
---

## Overview

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 packages

- `github.com/mattermost/mattermost-server >= 11.6.0, < 11.6.1`
- `github.com/mattermost/mattermost-server >= 11.5.0, < 11.5.5`
- `github.com/mattermost/mattermost-server >= 10.11.0, < 10.11.17`
- `github.com/mattermost/mattermost/server/v8 >= 8.0.0-20250731163400-5b955468ea1e, < 8.0.0-20260501144115-7d6816abdfd1`

## Remediation

Upgrade to a patched release:

- `github.com/mattermost/mattermost-server 11.6.1`
- `github.com/mattermost/mattermost-server 11.5.5`
- `github.com/mattermost/mattermost-server 10.11.17`
- `github.com/mattermost/mattermost/server/v8 8.0.0-20260501144115-7d6816abdfd1`