Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549
References
History

Fri, 13 Feb 2026 21:45:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost

Fri, 13 Feb 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 13 Feb 2026 10:45:00 +0000

Type Values Removed Values Added
Description Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549
Title Time-of-check time-of-use vulnerability in common teams API
Weaknesses CWE-367
References
Metrics cvssV3_1

{'score': 3.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published: 2026-02-13T10:30:03.445Z

Updated: 2026-02-13T17:02:25.985Z

Reserved: 2026-01-15T11:34:00.225Z

Link: CVE-2026-20796

cve-icon Vulnrichment

Updated: 2026-02-13T17:01:43.299Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-02-13T11:16:10.280

Modified: 2026-02-13T14:23:48.007

Link: CVE-2026-20796

cve-icon Redhat

No data.