CVE-2026-6739
Received Received - Intake
Privilege Escalation in Mattermost via Role Patch API

Publication date: 2026-06-12

Last updated on: 2026-06-12

Assigner: Mattermost, Inc.

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
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Meta Information
Published
2026-06-12
Last Modified
2026-06-12
Generated
2026-06-12
AI Q&A
2026-06-12
EPSS Evaluated
N/A
NVD
CVE-2026-6739
EUVD
EUVD-2026-36499
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
mattermost mattermost to 11.6.1 (inc)
mattermost mattermost to 11.5.4 (inc)
mattermost mattermost to 10.11.15 (inc)
mattermost mattermost to 10.11.16 (inc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
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Executive Summary

This vulnerability exists in certain versions of Mattermost (11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, and 10.11.x <= 10.11.16) where the system fails to require system-level permission when patching protected default system roles.

As a result, authenticated users who have delegated user-management permissions can escalate their privileges by altering built-in role permissions through the role patch API.

Impact Analysis

This vulnerability allows users with certain delegated permissions to escalate their privileges beyond what is intended by modifying built-in role permissions.

Such privilege escalation can lead to unauthorized access to sensitive information or administrative functions, potentially compromising the confidentiality and integrity of the system.

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