CVE-2026-10542 Playbooks channel action update validation issue

Mattermost versions 11.9.x = 11.9.0, 11.8.x = 11.8.4, 11.7.x = 11.7.7, 10.11.x = 10.11.22 fail to validate channel action ownership which allows channel managers to update actions in other channels via the channel action update endpoint.. Mattermost Advisory ID: MMSA-2026-00692...

EUVD-2026-77366

Mattermost versions 11.9.x = 11.9.0, 11.8.x = 11.8.4, 11.7.x = 11.7.7, 10.11.x = 10.11.22 fail to validate channel action ownership which allows channel managers to update actions in other channels via the channel action update endpoint.. Mattermost Advisory ID: MMSA-2026-00692...

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...

Incorrect Authorization

Overview Affected versions of this package are vulnerable to Incorrect Authorization in the updateChannelAction function, which does not sufficiently check user permissions before executing a delete operation. Any user can delete posts containing actions posted by the Playbooks bot. Remediation...