CVE-2026-4265

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to validate team-specific upload_file permissions which allows a guest user to post files in channels where they lack upload_file permission via uploading files in a team where they have permission and reusing the file metadata in a POST request to a different team. Mattermost Advisory ID: MMSA-2025-00553

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 LOW

Availability Impact NONE

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

18 Mar 2026, 17:41

Type	Values Removed	Values Added
References	~~() https://mattermost.com/security-updates -~~	() https://mattermost.com/security-updates - Vendor Advisory
Summary		(es) Las versiones de Mattermost 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fallan al validar los permisos de upload_file específicos del equipo, lo que permite a un usuario invitado publicar archivos en canales donde carece del permiso de upload_file, mediante la carga de archivos en un equipo donde tiene permiso y la reutilización de los metadatos del archivo en una solicitud POST a un equipo diferente. ID de Aviso de Mattermost: MMSA-2025-00553
CPE		cpe:2.3:a:mattermost:mattermost_server::::::::
First Time		Mattermost Mattermost mattermost Server

16 Mar 2026, 14:20

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-03-16 14:20

Updated : 2026-03-18 17:41

NVD link : CVE-2026-4265

Mitre link : CVE-2026-4265

CVE.ORG link : CVE-2026-4265

JSON object : View

Products Affected

mattermost

mattermost_server

CWE

CWE-863

Incorrect Authorization

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