CVE-2026-18256

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to properly restrict private teams from public team search results, which allows an authenticated user without permission to list private teams to disclose the ID, name, and display name of private teams via a modified team search request. Mattermost Advisory ID: MMSA-2026-00748

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 LOW

Integrity Impact NONE

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::::::::
	cpe:2.3:a:mattermost:mattermost_server:11.10.0:::::::*

History

29 Oct 2026, 18:08

Type	Values Removed	Values Added
First Time		Mattermost mattermost Server Mattermost
References	~~() https://mattermost.com/security-updates -~~	() https://mattermost.com/security-updates - Vendor Advisory
CPE		cpe:2.3:a:mattermost:mattermost_server:11.10.0:::::::* cpe:2.3:a:mattermost:mattermost_server::::::::

16 Oct 2026, 08:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-16 08:17

Updated : 2026-10-29 18:08

NVD link : CVE-2026-18256

Mitre link : CVE-2026-18256

CVE.ORG link : CVE-2026-18256

JSON object : View

Products Affected

mattermost

mattermost_server

CWE

CWE-863

Incorrect Authorization

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