{
"id": "GHSA-jp3f-x449-4q75",
"aliases": [
"CVE-2026-6334"
],
"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",
"summary": "Mattermost doesn't enforce client identity binding during the OAuth authorization code redemption flow",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "11.5.0"
},
{
"fixed": "11.5.2"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost/server/v8",
"ecosystem": "Go"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.14"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost/server/v8",
"ecosystem": "Go"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "8.0.0-20260318173148-e9ae890a013b"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost/server/v8",
"ecosystem": "Go"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.3.2-0.20260318173148-e9ae890a013b"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
}
}
],
"modified": "2026-06-01T15:04:49Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N"
}
],
"published": "2026-05-18T09:31:47Z",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6334",
"type": "ADVISORY"
},
{
"url": "https://github.com/mattermost/mattermost/commit/e9ae890a013bb57989fcbdb548d8b7b86b240237",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost",
"type": "PACKAGE"
},
{
"url": "https://mattermost.com/security-updates",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-305"
],
"severity": "LOW",
"github_reviewed": true,
"nvd_published_at": "2026-05-18T08:16:14Z",
"github_reviewed_at": "2026-06-01T15:04:48Z"
}
}