CVEvulnerability

CVE-2026-9816

8.3 HIGH Published 2026-08-17 Modified 2026-08-19 Official page ↗
Status
Analyzed
Published
2026-08-17
Last modified
2026-08-19
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.3 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
Weaknesses
CWE-863

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 configurations

• mattermost mattermost server (>= 10.11.0 < 10.11.22) • mattermost mattermost server (>= 11.7.0 < 11.7.7) • mattermost mattermost server (>= 11.8.0 < 11.8.4)

Related

Weakness · CWE (1)

  • CWE-863 Incorrect Authorization weakness

References