Description
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
Affected products
mattermost: mattermost server
References1
- mattermost.com/security-updates Vendor Advisory
Metrics
- CVSS 3.1
-
4.2
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N - EPSS — exploit probability
- 0% percentile: 16 · as of 11 November 2026
- CWE
- CWE-863
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