CVE-2026-3473
Published:May 22, 2026
Updated:June 11, 2026
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
Affected Packages
github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.15Fix Suggestion:
Update to version v10.11.15github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.4.0 <v11.4.5Fix Suggestion:
Update to version v11.4.5github.com/mattermost/mattermost (GO):
Affected version(s) =v11.6.0 <v11.6.1Fix Suggestion:
Update to version v11.6.1github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.5.0 <v11.5.4Fix Suggestion:
Update to version v11.5.4Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
6
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.9
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Authorization Bypass Through User-Controlled Key
EPSS
Base Score:
0.03