CVE-2026-10819 MEDIUM

CVE-2026-10819: Mattermost Server Denial of Service via Animated GIF Emoji Upload

Vendor Mattermost
Product Mattermost
Weakness CWE-409
Published July 27, 2026
Last update July 27, 2026
View on NVD All CVEs

CVSS base score

6.5/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality None
Integrity None

CVSS vector

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

What the vulnerability does

01Description

Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploads, which allows an authenticated attacker to cause a denial of service via a crafted animated GIF uploaded as a custom emoji.. Mattermost Advisory ID: MMSA-2026-00695

Key dates

02Disclosure timeline

July 27, 2026 CVE published
July 27, 2026 Record updated