# CVE-2026-10080

## Summary

- **CVE ID:** CVE-2026-10080
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-704
- **Published:** Aug 17, 2026
- **Last Modified:** Aug 18, 2026

## 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

## Affected Products

- Mattermost — Mattermost (11.7.0)
- Mattermost — Mattermost (10.11.0)
- Mattermost — Mattermost (11.8.0)
- Mattermost — Mattermost (11.9.0)
- Mattermost — Mattermost (11.7.7)
- Mattermost — Mattermost (10.11.22)
- Mattermost — Mattermost (11.8.4)

## References

- [CNA](https://mattermost.com/security-updates)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.30%
- **EPSS Percentile:** 22.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._