CVE-2026-20796 LOW

CVE-2026-20796: Time-of-check time-of-use vulnerability in common teams API

Vendor Mattermost
Product Mattermost
Weakness CWE-367
Published February 13, 2026
Last update February 13, 2026
View on NVD All CVEs

CVSS base score

3.1/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality Low
Integrity None

CVSS vector

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

What the vulnerability does

01Description

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

Key dates

02Disclosure timeline

February 13, 2026 CVE published
February 13, 2026 Record updated