CVE-2026-16047
Board channel linking without read channel permission validation
CVSS Score
4.3
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate that users have read access to a channel before linking a board to it, which allows an authenticated attacker to discover the membership of private channels on the same team via creating, patching, importing, or bulk-creating boards with an arbitrary channelId. Mattermost Advisory ID: MMSA-2026-00674
| CWE | CWE-862 |
| 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:L/PR:L/UI:N/S:U/C:L/I:N/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None
Affected Versions
Mattermost / Mattermost
11.7.0 ≤ 11.7.6 10.11.0 ≤ 10.11.21 11.8.0 ≤ 11.8.3
Credits
GuyNesher