CVE-2026-8823

User Manager can demote bot accounts to guest without bot-management permission

Published Jun 22, 2026 CVSS 3.1 · 3.8 Low EPSS < 1% KEV · Not listed
Description
Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669

Remediation

Vendor Solution

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

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-xmfh-3ccg-c9fx Mattermost has an Incorrect Authorization issue
References
History
Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Description Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669
Title User Manager can demote bot accounts to guest without bot-management permission
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:N/I:L/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Jun 22, 2026, 4:12 PM
Reserved
May 18, 2026, 10:05 AM
Status
Analyzed
Published
Jun 22, 2026, 4:16 PM
Modified
Jun 26, 2026, 4:39 PM