Is CVE-2026-10080 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-10080?

CVE-2026-10080 has a CVSS v3 severity of MEDIUM (6.5).

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CVE-2026-10080

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