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
Published: 2026-05-22
Score: 5.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

Update Mattermost to versions 11.7.0, 11.6.1, 11.5.4, 11.4.5, 10.11.15 or higher.

Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-7pf2-9c95-w332 Mattermost doesn't validate file ownership and access control
References
History

Tue, 26 May 2026 13:45:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server

Fri, 22 May 2026 13:45:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost

Fri, 22 May 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 22 May 2026 11:00:00 +0000

Type Values Removed Values Added
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
Title Improper file ownership validation in the Boards API allows unauthorised file access
Weaknesses CWE-639
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N'}


Subscriptions

Mattermost Mattermost Mattermost Server
cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-05-22T12:12:49.437Z

Reserved: 2026-03-03T12:57:13.379Z

Link: CVE-2026-3473

cve-icon Vulnrichment

Updated: 2026-05-22T12:12:45.995Z

cve-icon NVD

Status : Analyzed

Published: 2026-05-22T11:16:22.477

Modified: 2026-06-17T10:43:38.453

Link: CVE-2026-3473

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-22T13:30:35Z

Weaknesses