cbcvebase.
CVE-2026-6334
published 2026-05-18

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…

low3.8CVSS 3.1
AVNACLPRHUINSUCLILAN
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

Affected

8 ranges
VendorProductVersion rangeFixed in
github.commattermost_mattermost-server>= 0 < 5.3.2-0.20260318173148-e9ae890a013b5.3.2-0.20260318173148-e9ae890a013b
github.commattermost_mattermost_server_v8>= 0 < 8.0.0-20260318173148-e9ae890a013b8.0.0-20260318173148-e9ae890a013b
github.commattermost_mattermost_server_v8>= 10.11.0 < 10.11.1410.11.14
github.commattermost_mattermost_server_v8>= 11.5.0 < 11.5.211.5.2
mattermostmattermost10.11.0 – 10.11.13
mattermostmattermost11.5.0 – 11.5.1
mattermostmattermost_server>= 10.11.0 < 10.11.1410.11.14
mattermostmattermost_server>= 11.5.0 < 11.5.211.5.2