CVE-2026-16046 Missing run-state validation on finished playbook runs

Mattermost versions 11.7.x = 11.7.6, 10.11.x = 10.11.21 fail to enforce run-state validation on write operations for finished playbook runs which allows a run participant to modify status, checklists, retrospective content, ownership, and participants on completed runs via REST and GraphQL API...