CVSS 3.1
8.3 highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:HCVE-2026-9816
High (8.3) in mattermost mattermost server. EPSS 0.4% chance of exploitation in the next 30 days.
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
Severity
- EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 28% of CVEs (scores of 2026-10-31)
- CWE
- CWE-863
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mattermost:mattermost_server