CVE-2026-6689
Description
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
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/mattermost/mattermost-serverGo | >= 11.6.0, < 11.6.1 | 11.6.1 |
github.com/mattermost/mattermost-serverGo | >= 11.5.0, < 11.5.5 | 11.5.5 |
github.com/mattermost/mattermost-serverGo | >= 10.11.0, < 10.11.17 | 10.11.17 |
github.com/mattermost/mattermost/server/v8Go | >= 8.0.0-20250731163400-5b955468ea1e, < 8.0.0-20260501144115-7d6816abdfd1 | 8.0.0-20260501144115-7d6816abdfd1 |
Affected products
3<=11.6.1, <=11.5.4, <=10.11.16+ 1 more
- (no CPE)range: <=11.6.1, <=11.5.4, <=10.11.16
- (no CPE)range: <=11.6.1, <=11.5.4, <=10.11.15, <=10.11.16
- osv-coordsRange: < 0.0.20260827T195228-160000.1.1
Patches
Vulnerability mechanics
References
17- github.com/advisories/GHSA-c28q-m4gf-vg4qghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-6689ghsaADVISORY
- github.com/mattermost/mattermost/commit/2dea05864024b3254fb28c5ed679592e2b7cd672ghsaWEB
- github.com/mattermost/mattermost/commit/3a96344214b1a84df70d97052d46b6f2b40b0caaghsaWEB
- github.com/mattermost/mattermost/commit/479fc42d0ec6da48e76b59608233d90bfc69769dghsaWEB
- github.com/mattermost/mattermost/commit/7d6816abdfd170169f717aea43c5716a1f9ef6b0ghsaWEB
- github.com/mattermost/mattermost/commit/977c791e5b54bc14fdb96a2b3dacc85da5d8c623ghsaWEB
- github.com/mattermost/mattermost/pull/36188ghsaWEB
- github.com/mattermost/mattermost/pull/36375ghsaWEB
- github.com/mattermost/mattermost/pull/36383ghsaWEB
- github.com/mattermost/mattermost/pull/36384ghsaWEB
- github.com/mattermost/mattermost/pull/36402ghsaWEB
- github.com/mattermost/mattermost/releases/tag/v10.11.16ghsaWEB
- github.com/mattermost/mattermost/releases/tag/v11.5.5ghsaWEB
- github.com/mattermost/mattermost/releases/tag/v11.6.2ghsaWEB
- github.com/mattermost/mattermost/releases/tag/v11.7.0ghsaWEB
- mattermost.com/security-updatesnvdWEB
News mentions
1- Mattermost Discloses 7 CVEs: Privilege Escalation, Token Theft, and Federated File WriteVypr Intelligence · Jun 12, 2026