CVE-2026-15754
Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal
CVSS Score
4.2
EPSS Score
0.0%
EPSS Percentile
0th
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
| CWE | CWE-863 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Aug 17, 2026 |
| Last Updated | Aug 17, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Affected Versions
Mattermost / Mattermost
11.7.0 ≤ 11.7.6 11.8.0 ≤ 11.8.3
Credits
KennySki