Description
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize the active channel field returned by the user status API endpoints, which allows an authenticated user to learn the channel ID of a private channel another user is actively viewing via the status endpoints, without being a member of that channel. Mattermost Advisory ID: MMSA-2026-00765
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Mattermost Mattermost
Default version status: unaffected
11.9.0 to ≤ 11.9.1affected11.8.0 to ≤ 11.8.5affected11.7.0 to ≤ 11.7.10affected11.10.0 to ≤ 11.10.1affected11.11.0unaffected11.9.2unaffected11.8.6unaffected11.7.11unaffected11.10.2unaffected