CVE-2026-10819

MEDIUM

Mattermost Server Denial of Service via Animated GIF Emoji Upload

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00695
https://mattermost.com/security-updates

Scores

CVSS v3 6.5
EPSS 0.0024
EPSS Percentile 14.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-409
Status published
Products (9)
Mattermost/Mattermost 10.11.0 - 10.11.20
Mattermost/Mattermost 10.11.21
Mattermost/Mattermost 11.6.0 - 11.6.5
Mattermost/Mattermost 11.6.6
Mattermost/Mattermost 11.7.0 - 11.7.4
Mattermost/Mattermost 11.7.5
Mattermost/Mattermost 11.8.0 - 11.8.1
Mattermost/Mattermost 11.8.2
Mattermost/Mattermost 11.9.0
Published Jul 27, 2026
Tracked Since Jul 27, 2026