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
Published: 2026-05-22
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

Update Mattermost to versions 11.7.0, 11.6.1, 11.5.3, 11.5.4, 11.4.5, 10.11.15 or higher.

Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-37j2-3vv8-cf24 Mattermost doesn't validate the TIFF IFD offset in the image header before allocating memory
References
Link Providers
https://mattermost.com/security-updates cve-icon cve-icon
History

Tue, 26 May 2026 13:45:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server

Fri, 22 May 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 22 May 2026 12:45:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost

Fri, 22 May 2026 11:00:00 +0000

Type Values Removed Values Added
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
Title Denial of service via crafted TIFF file upload
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

Mattermost Mattermost Mattermost Server
cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-05-22T12:15:24.414Z

Reserved: 2026-04-07T16:22:49.762Z

Link: CVE-2026-5755

cve-icon Vulnrichment

Updated: 2026-05-22T12:15:21.063Z

cve-icon NVD

Status : Analyzed

Published: 2026-05-22T11:16:23.287

Modified: 2026-06-17T10:59:36.277

Link: CVE-2026-5755

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-22T12:30:27Z

Weaknesses