{
"id": "GHSA-cpf7-j4cf-vqx4",
"aliases": [
"CVE-2026-9803"
],
"details": "A flaw was found in Keycloak's ClientRegistrationAuth component. A remote unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with a malformed 'Authorization: Bearer' header to any client registration endpoint. This can lead to an ArrayIndexOutOfBoundsException, causing the server to return an HTTP 500 error and resulting in a Denial of Service (DoS) for the affected service.",
"summary": "Keycloak has an Out-of-bounds Read",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"last_affected": "26.4.7"
}
]
}
],
"package": {
"name": "org.keycloak:keycloak-services",
"ecosystem": "Maven"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "26.5.0"
},
{
"fixed": "26.6.3"
}
]
}
],
"package": {
"name": "org.keycloak:keycloak-services",
"ecosystem": "Maven"
}
}
],
"modified": "2026-07-01T21:27:37Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
}
],
"published": "2026-05-28T06:31:10Z",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9803",
"type": "ADVISORY"
},
{
"url": "https://github.com/keycloak/keycloak/issues/49433",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak/pull/49500",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak/pull/49617",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak/pull/49618",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak/commit/2b8692499e907e6205be0bd9c8a4da5d46f6ca30",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak/commit/3fc06909cc93eb5c4739a712fa350de625812e04",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak/commit/ef06df91d344c7e99fcb82987ef6adb854f30789",
"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-2026-9803",
"type": "WEB"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2482465",
"type": "WEB"
},
{
"url": "https://github.com/keycloak/keycloak",
"type": "PACKAGE"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-125"
],
"severity": "MODERATE",
"github_reviewed": true,
"nvd_published_at": "2026-05-28T06:16:29Z",
"github_reviewed_at": "2026-07-01T21:27:37Z"
}
}