CVE-2026-4055 MEDIUM

CVE-2026-4055: Insufficient permission validation on cross-team playbook run creation

Vendor Mattermost
Product Mattermost
Weakness CWE-863 · Incorrect authorization
Published May 21, 2026
Last update May 21, 2026
View on NVD All CVEs

CVSS base score

4.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality None
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

What the vulnerability does

01Description

Mattermost versions 11.5.x <= 11.5.1 fail to validate team-level run_create permission against the target team when creating a playbook run which allows an authenticated team member to create runs in teams where they lack permission via specifying a different team ID in the run creation API request. Mattermost Advisory ID: MMSA-2026-00629

Key dates

02Disclosure timeline

May 21, 2026 CVE published
May 21, 2026 Record updated