CVE-2026-6961 Details
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
A path traversal vulnerability has been identified in Mattermost versions 11.6.0 prior to 11.6.1, 11.5.0 prior to 11.5.4, and 10.11.0 prior to 10.11.16. The issue arises because Mattermost does not properly sanitize the FileInfo.Name received from federated peers during shared channel file synchronization. This lack of validation allows an attacker controlling a federated server to manipulate file paths and write files to arbitrary locations within the target server's filestore by exploiting path traversal sequences in the filename.
Users can upgrade to Mattermost versions 11.7.0, 11.5.7, or 10.11.17 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 13, 2026References 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-22 | Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mattermost mattermost server | >= 10.11.0, < 10.11.17 >= 11.5.0, < 11.5.5 >= 11.6.0, < 11.6.2 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 18, 2026 | Initial Analysis | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 12, 2026 | New CVE Received | [email protected] |