{
"id": "GHSA-m6qj-3mpp-57v8",
"aliases": [
"CVE-2026-9087"
],
"details": "A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId,\nidpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.",
"summary": "Keycloak: Insufficient verification proof scoping enables identity provider account linking attack and account compromise",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "26.6.3"
}
]
}
],
"package": {
"name": "org.keycloak:keycloak-services",
"ecosystem": "Maven"
}
}
],
"modified": "2026-06-26T09:30:45Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N"
}
],
"published": "2026-05-20T18:31:36Z",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9087",
"type": "ADVISORY"
},
{
"url": "https://github.com/keycloak/keycloak/commit/37dabf59d0b5ca3e5b3b272bcd3b2580e67b94dd",
"type": "WEB"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:25097",
"type": "WEB"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:25098",
"type": "WEB"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:30049",
"type": "WEB"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:30050",
"type": "WEB"
},
{
"url": "https://access.redhat.com/security/cve/CVE-2026-9087",
"type": "WEB"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480172",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak",
"type": "PACKAGE"
},
{
"url": "https://github.com/keycloak/keycloak/releases/tag/26.6.3",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-639"
],
"severity": "MODERATE",
"github_reviewed": true,
"nvd_published_at": "2026-05-20T17:16:32Z",
"github_reviewed_at": "2026-06-11T16:40:55Z"
}
}