CVE-2026-10080

Summary

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 Software

VendorProductVersion RangeStatus
MattermostMattermost11.7.0 <= 11.7.6affected
MattermostMattermost10.11.0 <= 10.11.21affected
MattermostMattermost11.8.0 <= 11.8.3affected
MattermostMattermost11.9.0unaffected
MattermostMattermost11.7.7unaffected
MattermostMattermost10.11.22unaffected
MattermostMattermost11.8.4unaffected

Weaknesses

  • CWE-704: CWE-704: Incorrect Type Conversion or Cast

References