CVE-2026-16048

Channel member roles accept out-of-scope roles

Published Aug 17, 2026 CVSS 3.1 · 6.3 Medium EPSS < 1% KEV · Not listed
Description
Mattermost versions 11.8.x <= 11.8.2, 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to restrict channel member role assignment to channel-scoped roles which allows a channel administrator to gain additional channel permissions via the channel member roles API.. Mattermost Advisory ID: MMSA-2026-00697

Remediation

Vendor Solution

Update Mattermost to versions 11.9.0, 11.8.3, 11.7.7, 10.11.22 or higher.

Tracking

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Advisories

No advisories available
References
History
Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Description Mattermost versions 11.8.x <= 11.8.2, 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to restrict channel member role assignment to channel-scoped roles which allows a channel administrator to gain additional channel permissions via the channel member roles API.. Mattermost Advisory ID: MMSA-2026-00697
Title Channel member roles accept out-of-scope roles
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Aug 17, 2026, 3:37 PM
Reserved
Jul 17, 2026, 9:45 AM
Status
Analyzed
Published
Aug 17, 2026, 3:16 PM
Modified
Aug 18, 2026, 8:42 PM