CVE-2026-6334

EUVD-2026-30743
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
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
3.1 LOW
NETWORK
HIGH
HIGH
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 1%
Affected Products (NVD)
VendorProductVersion
mattermostmattermost_server
10.11.0 ≤
𝑥
< 10.11.14
mattermostmattermost_server
11.5.0 ≤
𝑥
< 11.5.2
𝑥
= Vulnerable software versions
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mattermostmattermost
11.5.0 ≤
𝑥
≤ 11.5.1
CNA
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.13
CNA
Common Weakness Enumeration
References
https://mattermost.com/security-updates