Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.
Advisories
Source ID Title
EUVD EUVD EUVD-2025-25418 Mattermost Fails to Validate Remote Cluster Upload Sessions
Github GHSA Github GHSA GHSA-q453-638c-h4mr Mattermost Fails to Validate Remote Cluster Upload Sessions
Fixes

Solution

Update Mattermost to versions 10.11.0, 10.8.4, 10.5.9, 9.11.18, 10.9.3, 10.10.1 or higher.


Workaround

No workaround given by the vendor.

References
History

Thu, 21 Aug 2025 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Thu, 21 Aug 2025 12:45:00 +0000

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

Thu, 21 Aug 2025 08:15:00 +0000

Type Values Removed Values Added
Description Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.
Title Mattermost Shared Channel Upload Type Validation Bypass
Weaknesses CWE-434
References
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2025-08-21T13:57:13.759Z

Reserved: 2025-07-22T07:46:53.179Z

Link: CVE-2025-49222

cve-icon Vulnrichment

Updated: 2025-08-21T13:57:09.799Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2025-08-21T08:15:30.177

Modified: 2025-08-22T18:09:17.710

Link: CVE-2025-49222

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2025-08-21T12:30:44Z