CVE-2026-82920
Medium
Description
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724
SeverityMedium
CVSS5.5
Exploit probability—
Product
Mattermost Server
PublishedSep 14, 2026
First seenSep 14, 2026
Weakness typeCWE-863Incorrect authorization
How to fix
Update
- mattermost mattermost_server11.7.8, 11.8.5, 11.9.1 or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mattermost mattermost_server | 11.7.0 ≤ v < 11.7.8, 11.8.0 ≤ v < 11.8.5, 11.9.0 ≤ v < 11.9.1 | 11.7.8, 11.8.5, 11.9.1 |
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