Description
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to validate WebSocket command field types which allows an authenticated user to crash the plugin process and deny service to all Boards users via a custom_focalboard_SUBSCRIBE_TEAM message with a non-string teamId.. Mattermost Advisory ID: MMSA-2026-00687
Published: 2026-08-17
Score: 6.5 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

Update Mattermost to versions 11.9.0, 11.7.7, 10.11.22, 11.8.4 or higher.

Tracking

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Advisories

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References
History

Mon, 17 Aug 2026 23:45:00 +0000

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

Mon, 17 Aug 2026 22:15:00 +0000

Type Values Removed Values Added
Description Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to validate WebSocket command field types which allows an authenticated user to crash the plugin process and deny service to all Boards users via a custom_focalboard_SUBSCRIBE_TEAM message with a non-string teamId.. Mattermost Advisory ID: MMSA-2026-00687
Title Boards plugin panics on WebSocket command with non-string field types
Weaknesses CWE-704
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Subscriptions

Mattermost Mattermost
cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-08-17T22:04:30.830Z

Reserved: 2026-05-29T10:40:50.902Z

Link: CVE-2026-10080

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-17T22:16:58.607

Modified: 2026-08-17T22:16:58.607

Link: CVE-2026-10080

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T01:00:05Z

Weaknesses
  • CWE-704

    Incorrect Type Conversion or Cast