← Back

CVE-2026-9816

nvd nist
Published: Aug 17, 2026Modified: Aug 19, 2026

JSON object

Loading...
8.3
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
Exploitability: 2.8 / Impact: 5.5
Source: responsibledisclosure@mattermost.com (Secondary)

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

Affected (3)

Mattermost
1 product
Mattermost Server
Configuration A
3 vulnerable
Vulnerable SoftwareAffected Versions
Mattermost
Mattermost Server
From 10.11.0 to 10.11.22
Mattermost Server
From 11.7.0 to 11.7.7
Mattermost Server
From 11.8.0 to 11.8.4

Related CWEs

CWE-863
Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.

References (1)

Source: responsibledisclosure@mattermost.com
Vendor Advisory

Timeline

No history available yet.