Description
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect <instance-name>}} slash command.. Mattermost Advisory ID: MMSA-2026-00644
Published: 2026-06-22
Score: 5.4 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Solution

Update Mattermost to versions 11.8.0, 11.7.1, 11.6.3, 11.5.6, 10.11.18 or higher.

Tracking

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Advisories

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References
History

Mon, 22 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 22 Jun 2026 16:00:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost

Mon, 22 Jun 2026 13:45:00 +0000

Type Values Removed Values Added
Description Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect <instance-name>}} slash command.. Mattermost Advisory ID: MMSA-2026-00644
Title GitLab Plugin Allows Non-Admin Users to Modify Default Instance Configuration
Weaknesses CWE-862
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L'}


Subscriptions

Mattermost Mattermost
cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-06-22T15:39:29.821Z

Reserved: 2026-03-30T11:29:16.698Z

Link: CVE-2026-5139

cve-icon Vulnrichment

Updated: 2026-06-22T15:39:22.950Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-22T15:45:03Z

Weaknesses