CVE-2026-6340

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

CVSS v3 4.3 MEDIUM

4.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://mattermost.com/security-updates	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server::::::::

History

14 Oct 2026, 20:10

Type	Values Removed	Values Added
Summary		(es) Las versiones de Mattermost 11.5.x menor o igual que 11.5.1, 10.11.x menor o igual que 10.11.13, 11.4.x menor o igual que 11.4.3 no validan la estructura de archivo 7zip antes de procesar, lo que permite a un atacante autenticado causar agotamiento de memoria del servidor y denegación de servicio mediante la carga de un archivo 7zip especialmente diseñado con declaraciones de carpeta excesivas. ID de Aviso de Mattermost: MMSA-2026-00573

Information

Published : 2026-05-18 08:16

Updated : 2026-10-14 20:10

NVD link : CVE-2026-6340

Mitre link : CVE-2026-6340

CVE.ORG link : CVE-2026-6340

JSON object : View

Products Affected

mattermost

mattermost_server

CWE

CWE-789

Memory Allocation with Excessive Size Value

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