CVE-2026-6334

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to enforce client identity binding during the OAuth authorization code redemption flow which allows an authenticated OAuth client to redeem authorization codes issued to a different client via a crafted token exchange request.. Mattermost Advisory ID: MMSA-2026-00570

CVSS v3 3.1 LOW

3.1^/10

CVSS v3 : LOW

Vector :

Exploitability : 0.5 / Impact : 2.5

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required HIGH

User Interaction REQUIRED

Confidentiality Impact LOW

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::::::::

History

29 May 2026, 19:11

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

18 May 2026, 08:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-18 08:16

Updated : 2026-05-29 19:11

NVD link : CVE-2026-6334

Mitre link : CVE-2026-6334

CVE.ORG link : CVE-2026-6334

JSON object : View

Products Affected

mattermost

mattermost_server

CWE

CWE-305

Authentication Bypass by Primary Weakness

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