CVE-2026-6340

MEDIUM

Mattermost 10.11.0-10.11.13 11.4.0-11.4.3 11.5.0-11.5.1 - Authenticated Denial of Service via 7zip Archive Processing

Title source: llm
STIX 2.1

Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00573
https://mattermost.com/security-updates

Scores

CVSS v3 4.3
EPSS 0.0005
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:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-789
Status published
Products (8)
Mattermost/Mattermost 10.11.0 - 10.11.13
Mattermost/Mattermost 10.11.14
Mattermost/Mattermost 11.4.0 - 11.4.3
Mattermost/Mattermost 11.4.4
Mattermost/Mattermost 11.5.0 - 11.5.1
Mattermost/Mattermost 11.5.2
Mattermost/Mattermost 11.6.0
mattermost/mattermost_server 10.11.0 - 10.11.14
Published May 18, 2026
Tracked Since May 18, 2026