CVE-2026-26304
Received Received - Intake

Permission Bypass in Mattermost Playbook Run API Allows Unauthorized Run Creation

Publication date: 2026-03-16

Last updated on: 2026-03-18

Assigner: Mattermost, Inc.

Description
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542

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Meta Information

Published
2026-03-16
Last Modified
2026-03-18
Generated
2026-07-06
AI Q&A
2026-03-16
EPSS Evaluated
2026-07-05
NVD
CVE-2026-26304

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
mattermost mattermost_server From 11.2.0 (inc) to 11.2.3 (exc)
mattermost mattermost_server From 11.3.0 (inc) to 11.3.1 (exc)

Helpful Resources

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 Mattermost versions 11.3.x up to 11.3.0 and 11.2.x up to 11.2.2. It occurs because the software fails to verify the 'run_create' permission when the playbookId is empty. As a result, team members can create unauthorized runs using the playbook run API.

Impact Analysis

The impact of this vulnerability is that team members without proper authorization can create runs they should not be allowed to create. This could lead to unauthorized actions or changes within the Mattermost environment, potentially disrupting workflows or causing misuse of the playbook run functionality.

Compliance Impact

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