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CVE-2026-9816

—
CVSS 3.1
8.3 high
EPSS
<1%p18
Published
()
Modified
Description

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate BoardMember.Scheme* fields server-side on insert and archive-import paths which allows a board editor or non-guest team member to grant board admin to arbitrary users via POST /api/v2/boards/{boardID}/members and POST /api/v2/teams/{teamID}/archive/import.. Mattermost Advisory ID: MMSA-2026-00685

Vendors
mattermost
Products
mattermost server
Weakness
CWE-863
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
NVD CVE.org GitHub PoCs EPSS (0.3%)

In the news

No ingested article mentions this CVE yet.