{"id":"CVE-2026-6334","aliases":["GHSA-jp3f-x449-4q75","GO-2026-5474"],"url":"https://o3.security/vulnerability/CVE-2026-6334","summary":"OAuth authorization code client binding not enforced during token redemption in Mattermost","details":"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","published":"2026-05-18T06:33:56.008Z","modified":"2026-08-12T03:51:45.060342401Z","cvss":{"score":3.1,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N"},"epss":{"score":0.00118,"percentile":0.01994,"asOf":"2026-08-14"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"11.5.2"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"10.11.14"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"8.0.0-20260318173148-e9ae890a013b"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","fixedVersion":"5.3.2-0.20260318173148-e9ae890a013b"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6334.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6334"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:45.060342401Z"}}