Vulnerability Details CVE-2026-6739
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API.. Mattermost Advisory ID: MMSA-2026-00656
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 14.6%
CVSS Severity
CVSS v3 Score 6.7
References
Products affected by CVE-2026-6739
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cpe:2.3:a:mattermost:mattermost_server:10.11.0
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cpe:2.3:a:mattermost:mattermost_server:10.11.1
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cpe:2.3:a:mattermost:mattermost_server:10.11.10
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cpe:2.3:a:mattermost:mattermost_server:10.11.11
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cpe:2.3:a:mattermost:mattermost_server:10.11.12
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cpe:2.3:a:mattermost:mattermost_server:10.11.13
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cpe:2.3:a:mattermost:mattermost_server:10.11.14
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cpe:2.3:a:mattermost:mattermost_server:10.11.15
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cpe:2.3:a:mattermost:mattermost_server:10.11.16
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cpe:2.3:a:mattermost:mattermost_server:10.11.2
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cpe:2.3:a:mattermost:mattermost_server:10.11.3
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cpe:2.3:a:mattermost:mattermost_server:10.11.4
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cpe:2.3:a:mattermost:mattermost_server:10.11.5
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cpe:2.3:a:mattermost:mattermost_server:10.11.6
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cpe:2.3:a:mattermost:mattermost_server:10.11.7
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cpe:2.3:a:mattermost:mattermost_server:10.11.8
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cpe:2.3:a:mattermost:mattermost_server:10.11.9
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cpe:2.3:a:mattermost:mattermost_server:11.5.0
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cpe:2.3:a:mattermost:mattermost_server:11.5.1
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cpe:2.3:a:mattermost:mattermost_server:11.5.2
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cpe:2.3:a:mattermost:mattermost_server:11.5.3
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cpe:2.3:a:mattermost:mattermost_server:11.5.4
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cpe:2.3:a:mattermost:mattermost_server:11.6.0
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cpe:2.3:a:mattermost:mattermost_server:11.6.1