GitHub Advisoryadvisory · Go

GHSA-7pf2-9c95-w332 Mattermost doesn't validate file ownership and access control

HIGH Published 2026-05-26 Modified 2026-06-26 Official page ↗
Aliases
CVE-2026-3473
Ecosystem
Go
Packages
github.com/mattermost/mattermost-server
Severity
High
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Weaknesses
CWE-639
Reviewed
2026-06-26

Affected packages

• Go github.com/mattermost/mattermost-server: >= 11.6.0, < 11.6.1 → fixed in 11.6.1 • Go github.com/mattermost/mattermost-server: >= 11.5.0, < 11.5.4 → fixed in 11.5.4 • Go github.com/mattermost/mattermost-server: >= 11.4.0, < 11.4.5 → fixed in 11.4.5 • Go github.com/mattermost/mattermost-server: >= 10.11.0, < 10.11.15 → fixed in 10.11.15

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.

Related

Alias · CVE (1)

  • CVE-2026-3473 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… vulnerability

Weakness · CWE (1)

  • CWE-639 Authorization Bypass Through User-Controlled Key weakness

References