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CVE PROGRAM SOURCE RECORD5.9 Medium

CVE-2026-3473

Improper file ownership validation in the Boards API allows unauthorised file access

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Status
Published
Published
Updated
Assigning organization
Mattermost

Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.. Mattermost Advisory ID: MMSA-2026-00620

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Mattermost Mattermost

Default version status: unaffected

  • 11.6.0 to ≤ 11.6.0affected
  • 11.5.0 to ≤ 11.5.3affected
  • 11.4.0 to ≤ 11.4.4affected
  • 10.11.0 to ≤ 10.11.14affected
  • 11.7.0unaffected
  • 11.6.1unaffected
  • 11.5.4unaffected
  • 11.4.5unaffected
  • 10.11.15unaffected

References