Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718
CVSS Details
- CVSS 3.1 Base Score: 4.2
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N)
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