CVE-2026-10542

Mattermost versions 11.9.x ≤ 11.9.0, 11.8.x ≤ 11.8.4, 11.7.x ≤ 11.7.7, and 10.11.x ≤ 10.11.22 contain a validation flaw in the Playbooks channel action update endpoint . The failure to validate channel action ownership allows a channel manager to update actions belonging to other channels, leadin...