CVE-2026-6957

Mattermost Plugins versions <=1.1.5 fail to sanitize filenames received from federated peers before using them to construct export destination paths, which allows an administrator of a remote federated Mattermost server to write files to arbitrary locations within the target server's filestore via a malicious filename delivered through the shared-channel attachment sync protocol. Mattermost Advisory ID: MMSA-2026-00659

CVSS v3 8.0 HIGH

8.0^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.3 / Impact : 6.0

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://mattermost.com/security-updates	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:mattermost:legal_hold:*:*:*:*:*:mattermost:*:*

History

No history.

Information

Published : 2026-05-27 15:16

Updated : 2026-06-17 11:01

NVD link : CVE-2026-6957

Mitre link : CVE-2026-6957

CVE.ORG link : CVE-2026-6957

JSON object : View

Products Affected

mattermost

legal_hold

CWE

CWE-22

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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