CVE-2026-6334

LOW

OAuth authorization code client binding not enforced during token redemption in Mattermost

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00570
https://mattermost.com/security-updates

Scores

CVSS v3 3.1
EPSS 0.0003
EPSS Percentile 7.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-305
Status published
Products (5)
Mattermost/Mattermost 10.11.0 - 10.11.13
Mattermost/Mattermost 10.11.14
Mattermost/Mattermost 11.5.0 - 11.5.1
Mattermost/Mattermost 11.5.2
Mattermost/Mattermost 11.6.0
Published May 18, 2026
Tracked Since May 18, 2026