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CVE PROGRAM SOURCE RECORD6.5 Medium

CVE-2026-5755

Denial of service via crafted TIFF file upload

Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.2, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service (server OOM) via uploading a crafted TIFF file or posting a URL that serves one.. Mattermost Advisory ID: MMSA-2026-00648

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 ≤ 11.5.2affected
  • 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
  • 11.5.3unaffected
  • 11.5.4unaffected
  • 11.4.5unaffected
  • 10.11.15unaffected

References