PT-2026-42751 · Mattermost · Mattermost

Zephrfish

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Published

2026-05-22

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Updated

2026-05-22

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CVE-2026-5755

CVSS v3.1

6.5

Medium

VectorAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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

Fix

Resource Exhaustion

Weakness Enumeration

Related Identifiers

CVE-2026-5755

Affected Products

Mattermost