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
{
"cwe_ids": [
"CWE-305"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-01T15:04:48Z",
"nvd_published_at": "2026-05-18T08:16:14Z",
"severity": "LOW"
}