CVE-2026-6739

Mattermost: Delegated admins could patch protected default system roles

State: Published
Severity: 6.7 Medium
Published: Jun 12, 2026
Updated: Jun 13, 2026
Reserved: Apr 21, 2026

Description

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

Scores

CVSS	Score	Vector	Source
3.1	6.7 Medium	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L	Mattermost

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
MattermostMattermost	11.6.0 through 11.6.1Affected 11.5.0 through 11.5.4Affected 10.11.0 through 10.11.15Affected 10.11.0 through 10.11.16Affected 11.7.0Not affected 11.6.2Not affected 11.5.5Not affected 10.11.16Not affected 10.11.17Not affected

References

MMSA-2026-00656vendor-advisory

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