Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field.. Mattermost Advisory ID: MMSA-2026-00661

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Fixes

Solution

Update Mattermost to versions 11.7.0, 11.6.2, 11.5.5, 10.11.16, 10.11.17 or higher.


Workaround

No workaround given by the vendor.

References
History

Fri, 12 Jun 2026 18:45:00 +0000

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

Fri, 12 Jun 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Fri, 12 Jun 2026 17:15:00 +0000

Type Values Removed Values Added
Description Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field.. Mattermost Advisory ID: MMSA-2026-00661
Title CVE-2026-6961: Path traversal via unsanitized FileInfo.Name in Mattermost federation sync
Weaknesses CWE-22
References
Metrics cvssV3_1

{'score': 7.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-06-12T17:17:44.544Z

Reserved: 2026-04-24T15:22:26.743Z

Link: CVE-2026-6961

cve-icon Vulnrichment

Updated: 2026-06-12T17:17:41.028Z

cve-icon NVD

Status : Received

Published: 2026-06-12T17:16:27.410

Modified: 2026-06-12T17:16:27.410

Link: CVE-2026-6961

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-12T18:30:31Z

Weaknesses