CVE-2026-20796
Time-of-check time-of-use vulnerability in common teams API
Summary
Time-of-check time-of-use vulnerability in common teams API
Original description
The description as published by the source.
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
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
References
- advisory github.com
- advisory mattermost.com
- advisory nvd.nist.gov