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CVE-2026-3473 Details

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

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:7.1 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

CNA: [email protected]CVSS-B:5.9 MEDIUMVector:CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://mattermost.com/security-updates	[email protected]	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-639	Authorization Bypass Through User-Controlled Key	[email protected]

Affected Products

Product	Versions
mattermost mattermost server	>= 10.11.0, < 10.11.15 >= 11.4.0, < 11.4.5 >= 11.5.0, < 11.5.4 >= 11.6.0, < 11.6.1
CPE cpe:2.3:a:mattermost:mattermost_server:::::::: Remediation No remediation found in references.

Change History

5 change records found show changes

Date	Action	Recorded By
Jul 23, 2026	CVE Translated	[email protected]
Jun 17, 2026	CVE Modified	[email protected]
Jun 17, 2026	CVE Modified	CISA-ADP
May 22, 2026	Initial Analysis	[email protected]
May 22, 2026	New CVE Received	[email protected]