CVE-2026-3473
MEDIUM
mattermost
mattermost_server
NVD
CVSS Score
5.9
Severity
MEDIUM
Published
May 22, 2026
Vendor
mattermost
Description
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.. Mattermost Advisory ID: MMSA-2026-00620