Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the /api/v4/teams/{team_id}/channels/search_archived endpoint
/api/v4/teams/{team_id}/channels/search_archived
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-11776.json"
[ { "events": [ { "introduced": "0" }, { "fixed": "11.0.0" } ] } ]