CVE-2026-15814

Published: Sep 14, 2026Modified: Oct 7, 2026

6.5

Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitability: 2.8 / Impact: 3.6

Source: responsibledisclosure@mattermost.com (Secondary)

Description

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to limit the amount of memory allocated when decoding uploaded image files which allows an authenticated user to cause excessive server memory consumption and potential denial of service via uploading a specially crafted image as a profile picture, channel file attachment, team icon, or custom brand image. Mattermost Advisory ID: MMSA-2026-00719

Affected (4)

Products: Mattermost: Mattermost Server

Mattermost

1 product

Mattermost Server

Configuration A

4 vulnerable

Vulnerable Software	Affected Versions
Mattermost Mattermost Server	10.11.0 ≤ version < 10.11.23
Mattermost Mattermost Server	11.7.0 ≤ version < 11.7.8
Mattermost Mattermost Server	11.8.0 ≤ version < 11.8.5
Mattermost Mattermost Server	11.9.0 ≤ version < 11.9.1

Related CWEs

CWE-409

Improper Handling of Highly Compressed Data (Data Amplification)

The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.

References (1)

https://mattermost.com/security-updates

Source: responsibledisclosure@mattermost.com

Vendor Advisory

Timeline

No history available yet.