Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531

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Advisories

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Fixes

Solution

Update Mattermost to versions 11.4.0, 10.11.11 or higher.


Workaround

No workaround given by the vendor.

References
History

Wed, 18 Mar 2026 14:00:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server

Tue, 17 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Tue, 17 Mar 2026 10:00:00 +0000

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

Mon, 16 Mar 2026 20:45:00 +0000

Type Values Removed Values Added
Description Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531
Title Team Admin Privilege Escalation to Demote Members to Guest
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 3.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-03-17T13:37:17.914Z

Reserved: 2026-02-13T10:39:47.088Z

Link: CVE-2026-26230

cve-icon Vulnrichment

Updated: 2026-03-17T13:37:14.472Z

cve-icon NVD

Status : Analyzed

Published: 2026-03-16T21:16:33.480

Modified: 2026-03-18T13:56:13.130

Link: CVE-2026-26230

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-03-17T09:52:08Z

Weaknesses