CVE-2026-6334 LOW

CVE-2026-6334: OAuth authorization code client binding not enforced during token redemption in Mattermost

Vendor Mattermost
Product Mattermost
Weakness CWE-305
Published May 18, 2026
Last update May 18, 2026
View on NVD All CVEs

CVSS base score

3.1/10
Attack vector Network
Attack complexity High
Privileges required High
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N

What the vulnerability does

01Description

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

Key dates

02Disclosure timeline

May 18, 2026 CVE published
May 18, 2026 Record updated