CVE-2026-6689Network attack vector

Unauthorized invite-control changes via missing creation check

Published Jun 12, 2026 · Updated Jun 12, 2026

Missing authorization in Mattermost allows remote authenticated users to alter team invite controls during team creation. POST /api/v4/teams accepts allow_open_invite and allowed_domains without enforcing PermissionInviteUser, although update and patch paths perform that check. PermissionCreateTeam is sufficient to create a publicly joinable team or restrict membership by domain without the invite-user permission.

CVSS severity4.3
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Mattermost allows remote authenticated users to alter team invite controls during team creation. POST /api/v4/teams accepts allow_open_invite and allowed_domains without enforcing PermissionInviteUser, although update and patch paths perform that check. PermissionCreateTeam is sufficient to create a publicly joinable team or restrict membership by domain without the invite-user permission.

The record

CVE
CVE-2026-6689
Published
Jun 12, 2026
Updated
Jun 12, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-862
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.11.0 <=10.11.15
  2. Affected versionversion=10.11.0 <=10.11.16
  3. Affected versionversion=11.5.0 <=11.5.4
  4. Affected versionversion=11.6.0 <=11.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=10.11.0 <=10.11.15; version=10.11.0 <=10.11.16; version=11.5.0 <=11.5.4; version=11.6.0 <=11.6.1

Published CVSS scores

4.3Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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