CVE-2026-10080 Boards plugin panics on WebSocket command with non-string field types

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21, 11.8.x = 11.8.3 fails to validate WebSocket command field types which allows an authenticated user to crash the plugin process and deny service to all Boards users via a customfocalboardSUBSCRIBETEAM message with a non-string teamId...