Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to limit the size of remote image responses buffered in memory during local image proxy direct fetches, which allows a remote attacker to cause memory exhaustion on the server via a crafted oversized image response.. Mattermost Advisory ID: MMSA-2026-00726
Advisories

No advisories yet.

Fixes

Solution

Update Mattermost to versions 11.11.0, 11.10.1, 11.7.10, 11.9.2, 11.8.6 or higher.


Workaround

No workaround given by the vendor.

References
History

Fri, 16 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Fri, 16 Oct 2026 07:30:00 +0000

Type Values Removed Values Added
Description Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to limit the size of remote image responses buffered in memory during local image proxy direct fetches, which allows a remote attacker to cause memory exhaustion on the server via a crafted oversized image response.. Mattermost Advisory ID: MMSA-2026-00726
Title Mattermost local image proxy allows server memory exhaustion via unbounded image response buffering
Weaknesses CWE-770
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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-10-16T11:57:33.968Z

Reserved: 2026-07-20T07:26:18.823Z

Link: CVE-2026-16251

cve-icon Vulnrichment

Updated: 2026-10-16T11:57:28.590Z

cve-icon NVD

Status : Received

Published: 2026-10-16T08:17:12.527

Modified: 2026-10-16T12:16:38.557

Link: CVE-2026-16251

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses